Code
P0203
AUDI
P — Powertrain
Fuel injector failure, Powertrain Control Module (PCM) failure, Wiring issue
Views:
UK: 29
EN: 50
RU: 44
AI status
Completed
Completed
100%
Causes
- Open or shorted injector wiring harness to injector 3
- Corroded, loose or damaged injector connector/pin
- Failed fuel injector (internal open or short)
- Faulty PCM/injector driver
- Blown fuse or relay affecting injector power/PCM
- Intermittent wiring damage (chafing, rodent, heat)
Symptoms
- Check Engine Light (MIL) illuminated
- Rough idle or vibration, especially at idle
- Misfire detected on cylinder 3 (P0303 may also set)
- Loss of power, hesitation on acceleration
- Poor fuel economy and increased emissions
- Possible hard starting or no-start if severe
What to check
- Retrieve freeze frame and live data with a scan tool; note cylinder 3 misfire, fuel trim, and injector status
- Visually inspect wiring, connectors, and harness for damage, corrosion, or pin push-out at injector 3
- Check battery voltage and relevant fuses/relays for proper operation
- Measure injector 3 resistance at the connector (unplugged) and compare to manufacturer spec
- Back-probe injector connector with oscilloscope or DVOM (for pulse presence and voltage levels) while cranking/running
- Wiggle test wiring while monitoring for changes or intermittent faults
Signal parameters
- Injector coil resistance: typically ~2–16 ohms depending on high- or low-impedance design — consult Audi spec
- Resting circuit voltage at injector power feed: battery voltage (approx. 12–14 V with key on/engine running)
- Injector driver ground switching: PCM pulls injector low to energize; expect ~0 V on switched side when energized
- Injector pulse width: varies with load; small at idle (~1–3 ms) and longer under load; observable with scope
- No short to battery: no sustained 12 V on driver side when injector should be open
Diagnostic algorithm
- Connect a scan tool, read stored/ pending DTCs and freeze frame; confirm P0203 and note any related codes (P0303, P0200, etc.).
- Visually inspect injector 3 connector and harness for corrosion, pin damage, heat or rodent damage; repair obvious issues.
- Verify battery voltage and check injector fuse/relay circuits for proper voltage at the injector power feed with ignition ON.
- With connector unplugged, measure injector 3 coil resistance and compare to spec. Abnormal open or short indicates bad injector.
- Back-probe the injector harness with the engine cranking or running: confirm PCM provides pulse (switches ground) and that power feed is present.
- Use an oscilloscope to view pulse waveform for distortions or stuck-on driver; if no pulse present but PCM commands it, suspect wiring/PCM.
- Perform continuity and short-to-power/ground checks between injector pin and PCM connector/pin; repair any harness faults.
- If injector resistance and wiring are good but driver signal abnormal, test by swapping injectors between cylinders. If code follows injector, replace injector.
- If code remains on original cylinder after swapping injectors, and wiring checks out, consider PCM injector driver fault — consult dealer-level diagnostics and repair procedures before replacing PCM.
- Clear codes and test drive; confirm repair by ensuring code does not return and engine runs normally.
Likely causes
- Damaged connector or pin corrosion at injector 3
- Wiring short to battery or short to ground in injector 3 circuit
- Injector 3 has failed internally (open coil or short)
- PCM driver for injector 3 has failed (less common)
- Low battery voltage or fuse/relay issue feeding injectors
Fault status
Status
Injector Circuit/Open — Cylinder 3 (P0203). PCM detected abnormal electrical condition on fuel injector circuit for cylinder 3; MIL on.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
Workshop Manuals
Repair manuals for AUDI
11
6-speed manual gearbox 0B1, front-wheel drive — Workshop Manual (Edition 05.2014)
Workshop ManualAudi A3 (1997) – 1.6L 4-cylinder (2‑valve) Engine Mechanical Components Service Manual (AEH, AKL, APF) – Edition 07.2002
Workshop ManualAUDI A3 (2004) Workshop Manual — 2.0L FSI Turbo (4‑cyl, 4‑valve) Engine, Mechanics — Edition 03.2017
Workshop ManualAudi A3 2004 — Electrical System (Workshop Manual, Edition 02.2018)
Workshop ManualAudi A4 / A4 Cabriolet – 4.2 l V8 (5‑valve, timing chains) – Workshop Manual (Mechanics) – Edition 04.2007
Workshop ManualAudi A4 / A4 Cabriolet — Auxiliary Heater Workshop Manual (Edition 08.2004)
Workshop ManualAudi A4 / A4 Cabriolet (1.8T 4‑cyl turbo) — Motronic Injection & Ignition System Service Manual (Edition 01.2015)
Workshop ManualAudi A8 (2003) — Electrical System Workshop Manual (Edition 08.2014)
Workshop ManualAudi Q4 e-tron (Type F4) - Self-study Programme SSP 685
Workshop ManualAudi Q8 (2018) — Electrical System Workshop Manual (Edition 05.2019)
Workshop ManualAudi Servicing Manual — 7‑Speed Dual Clutch Transmission 0CJ / 0CL / 0CK / 0DN / 0DP / 0HL (Edition 05.2018)
Workshop ManualYour experience will help others
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Code
P0203
Generic
P — Powertrain
Cylinder 3 Injector A Circuit
Views:
UK: 24
EN: 85
RU: 45
AI status
Completed
Completed
100%
Causes
- Open or shorted injector wiring harness to injector 3
- Corroded, loose or damaged injector connector/pin
- Failed fuel injector (internal open or short)
- Faulty PCM/injector driver
- Blown fuse or relay affecting injector power/PCM
- Intermittent wiring damage (chafing, rodent, heat)
Symptoms
- Check Engine Light (MIL) illuminated
- Rough idle or vibration, especially at idle
- Misfire detected on cylinder 3 (P0303 may also set)
- Loss of power, hesitation on acceleration
- Poor fuel economy and increased emissions
- Possible hard starting or no-start if severe
What to check
- Retrieve freeze frame and live data with a scan tool; note cylinder 3 misfire, fuel trim, and injector status
- Visually inspect wiring, connectors, and harness for damage, corrosion, or pin push-out at injector 3
- Check battery voltage and relevant fuses/relays for proper operation
- Measure injector 3 resistance at the connector (unplugged) and compare to manufacturer spec
- Back-probe injector connector with oscilloscope or DVOM (for pulse presence and voltage levels) while cranking/running
- Wiggle test wiring while monitoring for changes or intermittent faults
Signal parameters
- Injector coil resistance: typically ~2–16 ohms depending on high- or low-impedance design — consult Audi spec
- Resting circuit voltage at injector power feed: battery voltage (approx. 12–14 V with key on/engine running)
- Injector driver ground switching: PCM pulls injector low to energize; expect ~0 V on switched side when energized
- Injector pulse width: varies with load; small at idle (~1–3 ms) and longer under load; observable with scope
- No short to battery: no sustained 12 V on driver side when injector should be open
Diagnostic algorithm
- Connect a scan tool, read stored/ pending DTCs and freeze frame; confirm P0203 and note any related codes (P0303, P0200, etc.).
- Visually inspect injector 3 connector and harness for corrosion, pin damage, heat or rodent damage; repair obvious issues.
- Verify battery voltage and check injector fuse/relay circuits for proper voltage at the injector power feed with ignition ON.
- With connector unplugged, measure injector 3 coil resistance and compare to spec. Abnormal open or short indicates bad injector.
- Back-probe the injector harness with the engine cranking or running: confirm PCM provides pulse (switches ground) and that power feed is present.
- Use an oscilloscope to view pulse waveform for distortions or stuck-on driver; if no pulse present but PCM commands it, suspect wiring/PCM.
- Perform continuity and short-to-power/ground checks between injector pin and PCM connector/pin; repair any harness faults.
- If injector resistance and wiring are good but driver signal abnormal, test by swapping injectors between cylinders. If code follows injector, replace injector.
- If code remains on original cylinder after swapping injectors, and wiring checks out, consider PCM injector driver fault — consult dealer-level diagnostics and repair procedures before replacing PCM.
- Clear codes and test drive; confirm repair by ensuring code does not return and engine runs normally.
Likely causes
- Damaged connector or pin corrosion at injector 3
- Wiring short to battery or short to ground in injector 3 circuit
- Injector 3 has failed internally (open coil or short)
- PCM driver for injector 3 has failed (less common)
- Low battery voltage or fuse/relay issue feeding injectors
Fault status
Status
Injector Circuit/Open — Cylinder 3 (P0203). PCM detected abnormal electrical condition on fuel injector circuit for cylinder 3; MIL on.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
Workshop Manuals
Available brands with manuals
2
AUDI 11
6-speed manual gearbox 0B1, front-wheel drive — Workshop Manual (Edition 05.2014)
Workshop ManualAudi A3 (1997) – 1.6L 4-cylinder (2‑valve) Engine Mechanical Components Service Manual (AEH, AKL, APF) – Edition 07.2002
Workshop ManualAUDI A3 (2004) Workshop Manual — 2.0L FSI Turbo (4‑cyl, 4‑valve) Engine, Mechanics — Edition 03.2017
Workshop ManualAudi A3 2004 — Electrical System (Workshop Manual, Edition 02.2018)
Workshop ManualAudi A4 / A4 Cabriolet – 4.2 l V8 (5‑valve, timing chains) – Workshop Manual (Mechanics) – Edition 04.2007
Workshop ManualAudi A4 / A4 Cabriolet — Auxiliary Heater Workshop Manual (Edition 08.2004)
Workshop ManualAudi A4 / A4 Cabriolet (1.8T 4‑cyl turbo) — Motronic Injection & Ignition System Service Manual (Edition 01.2015)
Workshop ManualAudi A8 (2003) — Electrical System Workshop Manual (Edition 08.2014)
Workshop ManualAudi Q4 e-tron (Type F4) - Self-study Programme SSP 685
Workshop ManualAudi Q8 (2018) — Electrical System Workshop Manual (Edition 05.2019)
Workshop ManualAudi Servicing Manual — 7‑Speed Dual Clutch Transmission 0CJ / 0CL / 0CK / 0DN / 0DP / 0HL (Edition 05.2018)
Workshop ManualLAND ROVER 3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualLand Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop ManualYour experience will help others
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Code
P0203
GWM
P — Powertrain
- Injector malfunction - cylinder 3
Views:
UK: 0
EN: 3
RU: 5
AI status
Completed
Completed
100%
Causes
- Open or shorted injector wiring harness to injector 3
- Corroded, loose or damaged injector connector/pin
- Failed fuel injector (internal open or short)
- Faulty PCM/injector driver
- Blown fuse or relay affecting injector power/PCM
- Intermittent wiring damage (chafing, rodent, heat)
Symptoms
- Check Engine Light (MIL) illuminated
- Rough idle or vibration, especially at idle
- Misfire detected on cylinder 3 (P0303 may also set)
- Loss of power, hesitation on acceleration
- Poor fuel economy and increased emissions
- Possible hard starting or no-start if severe
What to check
- Retrieve freeze frame and live data with a scan tool; note cylinder 3 misfire, fuel trim, and injector status
- Visually inspect wiring, connectors, and harness for damage, corrosion, or pin push-out at injector 3
- Check battery voltage and relevant fuses/relays for proper operation
- Measure injector 3 resistance at the connector (unplugged) and compare to manufacturer spec
- Back-probe injector connector with oscilloscope or DVOM (for pulse presence and voltage levels) while cranking/running
- Wiggle test wiring while monitoring for changes or intermittent faults
Signal parameters
- Injector coil resistance: typically ~2–16 ohms depending on high- or low-impedance design — consult Audi spec
- Resting circuit voltage at injector power feed: battery voltage (approx. 12–14 V with key on/engine running)
- Injector driver ground switching: PCM pulls injector low to energize; expect ~0 V on switched side when energized
- Injector pulse width: varies with load; small at idle (~1–3 ms) and longer under load; observable with scope
- No short to battery: no sustained 12 V on driver side when injector should be open
Diagnostic algorithm
- Connect a scan tool, read stored/ pending DTCs and freeze frame; confirm P0203 and note any related codes (P0303, P0200, etc.).
- Visually inspect injector 3 connector and harness for corrosion, pin damage, heat or rodent damage; repair obvious issues.
- Verify battery voltage and check injector fuse/relay circuits for proper voltage at the injector power feed with ignition ON.
- With connector unplugged, measure injector 3 coil resistance and compare to spec. Abnormal open or short indicates bad injector.
- Back-probe the injector harness with the engine cranking or running: confirm PCM provides pulse (switches ground) and that power feed is present.
- Use an oscilloscope to view pulse waveform for distortions or stuck-on driver; if no pulse present but PCM commands it, suspect wiring/PCM.
- Perform continuity and short-to-power/ground checks between injector pin and PCM connector/pin; repair any harness faults.
- If injector resistance and wiring are good but driver signal abnormal, test by swapping injectors between cylinders. If code follows injector, replace injector.
- If code remains on original cylinder after swapping injectors, and wiring checks out, consider PCM injector driver fault — consult dealer-level diagnostics and repair procedures before replacing PCM.
- Clear codes and test drive; confirm repair by ensuring code does not return and engine runs normally.
Likely causes
- Damaged connector or pin corrosion at injector 3
- Wiring short to battery or short to ground in injector 3 circuit
- Injector 3 has failed internally (open coil or short)
- PCM driver for injector 3 has failed (less common)
- Low battery voltage or fuse/relay issue feeding injectors
Fault status
Status
Injector Circuit/Open — Cylinder 3 (P0203). PCM detected abnormal electrical condition on fuel injector circuit for cylinder 3; MIL on.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
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Code
P0203
HUMMER
P — Powertrain
Injector 3 Control Circuit
Views:
UK: 9
EN: 34
RU: 31
AI status
Completed
Completed
100%
Causes
- Open or shorted injector wiring harness to injector 3
- Corroded, loose or damaged injector connector/pin
- Failed fuel injector (internal open or short)
- Faulty PCM/injector driver
- Blown fuse or relay affecting injector power/PCM
- Intermittent wiring damage (chafing, rodent, heat)
Symptoms
- Check Engine Light (MIL) illuminated
- Rough idle or vibration, especially at idle
- Misfire detected on cylinder 3 (P0303 may also set)
- Loss of power, hesitation on acceleration
- Poor fuel economy and increased emissions
- Possible hard starting or no-start if severe
What to check
- Retrieve freeze frame and live data with a scan tool; note cylinder 3 misfire, fuel trim, and injector status
- Visually inspect wiring, connectors, and harness for damage, corrosion, or pin push-out at injector 3
- Check battery voltage and relevant fuses/relays for proper operation
- Measure injector 3 resistance at the connector (unplugged) and compare to manufacturer spec
- Back-probe injector connector with oscilloscope or DVOM (for pulse presence and voltage levels) while cranking/running
- Wiggle test wiring while monitoring for changes or intermittent faults
Signal parameters
- Injector coil resistance: typically ~2–16 ohms depending on high- or low-impedance design — consult Audi spec
- Resting circuit voltage at injector power feed: battery voltage (approx. 12–14 V with key on/engine running)
- Injector driver ground switching: PCM pulls injector low to energize; expect ~0 V on switched side when energized
- Injector pulse width: varies with load; small at idle (~1–3 ms) and longer under load; observable with scope
- No short to battery: no sustained 12 V on driver side when injector should be open
Diagnostic algorithm
- Connect a scan tool, read stored/ pending DTCs and freeze frame; confirm P0203 and note any related codes (P0303, P0200, etc.).
- Visually inspect injector 3 connector and harness for corrosion, pin damage, heat or rodent damage; repair obvious issues.
- Verify battery voltage and check injector fuse/relay circuits for proper voltage at the injector power feed with ignition ON.
- With connector unplugged, measure injector 3 coil resistance and compare to spec. Abnormal open or short indicates bad injector.
- Back-probe the injector harness with the engine cranking or running: confirm PCM provides pulse (switches ground) and that power feed is present.
- Use an oscilloscope to view pulse waveform for distortions or stuck-on driver; if no pulse present but PCM commands it, suspect wiring/PCM.
- Perform continuity and short-to-power/ground checks between injector pin and PCM connector/pin; repair any harness faults.
- If injector resistance and wiring are good but driver signal abnormal, test by swapping injectors between cylinders. If code follows injector, replace injector.
- If code remains on original cylinder after swapping injectors, and wiring checks out, consider PCM injector driver fault — consult dealer-level diagnostics and repair procedures before replacing PCM.
- Clear codes and test drive; confirm repair by ensuring code does not return and engine runs normally.
Likely causes
- Damaged connector or pin corrosion at injector 3
- Wiring short to battery or short to ground in injector 3 circuit
- Injector 3 has failed internally (open coil or short)
- PCM driver for injector 3 has failed (less common)
- Low battery voltage or fuse/relay issue feeding injectors
Fault status
Status
Injector Circuit/Open — Cylinder 3 (P0203). PCM detected abnormal electrical condition on fuel injector circuit for cylinder 3; MIL on.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
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Code
P0203
ISUZU
P — Powertrain
Injector Circuit - Cylinder 3
Views:
UK: 16
EN: 31
RU: 30
AI status
Completed
Completed
100%
Causes
- Open or shorted injector wiring harness to injector 3
- Corroded, loose or damaged injector connector/pin
- Failed fuel injector (internal open or short)
- Faulty PCM/injector driver
- Blown fuse or relay affecting injector power/PCM
- Intermittent wiring damage (chafing, rodent, heat)
Symptoms
- Check Engine Light (MIL) illuminated
- Rough idle or vibration, especially at idle
- Misfire detected on cylinder 3 (P0303 may also set)
- Loss of power, hesitation on acceleration
- Poor fuel economy and increased emissions
- Possible hard starting or no-start if severe
What to check
- Retrieve freeze frame and live data with a scan tool; note cylinder 3 misfire, fuel trim, and injector status
- Visually inspect wiring, connectors, and harness for damage, corrosion, or pin push-out at injector 3
- Check battery voltage and relevant fuses/relays for proper operation
- Measure injector 3 resistance at the connector (unplugged) and compare to manufacturer spec
- Back-probe injector connector with oscilloscope or DVOM (for pulse presence and voltage levels) while cranking/running
- Wiggle test wiring while monitoring for changes or intermittent faults
Signal parameters
- Injector coil resistance: typically ~2–16 ohms depending on high- or low-impedance design — consult Audi spec
- Resting circuit voltage at injector power feed: battery voltage (approx. 12–14 V with key on/engine running)
- Injector driver ground switching: PCM pulls injector low to energize; expect ~0 V on switched side when energized
- Injector pulse width: varies with load; small at idle (~1–3 ms) and longer under load; observable with scope
- No short to battery: no sustained 12 V on driver side when injector should be open
Diagnostic algorithm
- Connect a scan tool, read stored/ pending DTCs and freeze frame; confirm P0203 and note any related codes (P0303, P0200, etc.).
- Visually inspect injector 3 connector and harness for corrosion, pin damage, heat or rodent damage; repair obvious issues.
- Verify battery voltage and check injector fuse/relay circuits for proper voltage at the injector power feed with ignition ON.
- With connector unplugged, measure injector 3 coil resistance and compare to spec. Abnormal open or short indicates bad injector.
- Back-probe the injector harness with the engine cranking or running: confirm PCM provides pulse (switches ground) and that power feed is present.
- Use an oscilloscope to view pulse waveform for distortions or stuck-on driver; if no pulse present but PCM commands it, suspect wiring/PCM.
- Perform continuity and short-to-power/ground checks between injector pin and PCM connector/pin; repair any harness faults.
- If injector resistance and wiring are good but driver signal abnormal, test by swapping injectors between cylinders. If code follows injector, replace injector.
- If code remains on original cylinder after swapping injectors, and wiring checks out, consider PCM injector driver fault — consult dealer-level diagnostics and repair procedures before replacing PCM.
- Clear codes and test drive; confirm repair by ensuring code does not return and engine runs normally.
Likely causes
- Damaged connector or pin corrosion at injector 3
- Wiring short to battery or short to ground in injector 3 circuit
- Injector 3 has failed internally (open coil or short)
- PCM driver for injector 3 has failed (less common)
- Low battery voltage or fuse/relay issue feeding injectors
Fault status
Status
Injector Circuit/Open — Cylinder 3 (P0203). PCM detected abnormal electrical condition on fuel injector circuit for cylinder 3; MIL on.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
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Code
P0203
LAND ROVER
P — Powertrain
Cylinder with defect in the injector circuit 3
Views:
UK: 3
EN: 16
RU: 25
AI status
Completed
Completed
100%
Causes
- Open or shorted injector wiring harness to injector 3
- Corroded, loose or damaged injector connector/pin
- Failed fuel injector (internal open or short)
- Faulty PCM/injector driver
- Blown fuse or relay affecting injector power/PCM
- Intermittent wiring damage (chafing, rodent, heat)
Symptoms
- Check Engine Light (MIL) illuminated
- Rough idle or vibration, especially at idle
- Misfire detected on cylinder 3 (P0303 may also set)
- Loss of power, hesitation on acceleration
- Poor fuel economy and increased emissions
- Possible hard starting or no-start if severe
What to check
- Retrieve freeze frame and live data with a scan tool; note cylinder 3 misfire, fuel trim, and injector status
- Visually inspect wiring, connectors, and harness for damage, corrosion, or pin push-out at injector 3
- Check battery voltage and relevant fuses/relays for proper operation
- Measure injector 3 resistance at the connector (unplugged) and compare to manufacturer spec
- Back-probe injector connector with oscilloscope or DVOM (for pulse presence and voltage levels) while cranking/running
- Wiggle test wiring while monitoring for changes or intermittent faults
Signal parameters
- Injector coil resistance: typically ~2–16 ohms depending on high- or low-impedance design — consult Audi spec
- Resting circuit voltage at injector power feed: battery voltage (approx. 12–14 V with key on/engine running)
- Injector driver ground switching: PCM pulls injector low to energize; expect ~0 V on switched side when energized
- Injector pulse width: varies with load; small at idle (~1–3 ms) and longer under load; observable with scope
- No short to battery: no sustained 12 V on driver side when injector should be open
Diagnostic algorithm
- Connect a scan tool, read stored/ pending DTCs and freeze frame; confirm P0203 and note any related codes (P0303, P0200, etc.).
- Visually inspect injector 3 connector and harness for corrosion, pin damage, heat or rodent damage; repair obvious issues.
- Verify battery voltage and check injector fuse/relay circuits for proper voltage at the injector power feed with ignition ON.
- With connector unplugged, measure injector 3 coil resistance and compare to spec. Abnormal open or short indicates bad injector.
- Back-probe the injector harness with the engine cranking or running: confirm PCM provides pulse (switches ground) and that power feed is present.
- Use an oscilloscope to view pulse waveform for distortions or stuck-on driver; if no pulse present but PCM commands it, suspect wiring/PCM.
- Perform continuity and short-to-power/ground checks between injector pin and PCM connector/pin; repair any harness faults.
- If injector resistance and wiring are good but driver signal abnormal, test by swapping injectors between cylinders. If code follows injector, replace injector.
- If code remains on original cylinder after swapping injectors, and wiring checks out, consider PCM injector driver fault — consult dealer-level diagnostics and repair procedures before replacing PCM.
- Clear codes and test drive; confirm repair by ensuring code does not return and engine runs normally.
Likely causes
- Damaged connector or pin corrosion at injector 3
- Wiring short to battery or short to ground in injector 3 circuit
- Injector 3 has failed internally (open coil or short)
- PCM driver for injector 3 has failed (less common)
- Low battery voltage or fuse/relay issue feeding injectors
Fault status
Status
Injector Circuit/Open — Cylinder 3 (P0203). PCM detected abnormal electrical condition on fuel injector circuit for cylinder 3; MIL on.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
Workshop Manuals
Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualLand Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop ManualYour experience will help others
+100 karma for a short comment :)
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Send to email
Code
P0203
MITSUBISHI
P — Powertrain
No.3 injector system
Views:
UK: 6
EN: 21
RU: 29
AI status
Completed
Completed
100%
Causes
- Open or shorted injector wiring harness to injector 3
- Corroded, loose or damaged injector connector/pin
- Failed fuel injector (internal open or short)
- Faulty PCM/injector driver
- Blown fuse or relay affecting injector power/PCM
- Intermittent wiring damage (chafing, rodent, heat)
Symptoms
- Check Engine Light (MIL) illuminated
- Rough idle or vibration, especially at idle
- Misfire detected on cylinder 3 (P0303 may also set)
- Loss of power, hesitation on acceleration
- Poor fuel economy and increased emissions
- Possible hard starting or no-start if severe
What to check
- Retrieve freeze frame and live data with a scan tool; note cylinder 3 misfire, fuel trim, and injector status
- Visually inspect wiring, connectors, and harness for damage, corrosion, or pin push-out at injector 3
- Check battery voltage and relevant fuses/relays for proper operation
- Measure injector 3 resistance at the connector (unplugged) and compare to manufacturer spec
- Back-probe injector connector with oscilloscope or DVOM (for pulse presence and voltage levels) while cranking/running
- Wiggle test wiring while monitoring for changes or intermittent faults
Signal parameters
- Injector coil resistance: typically ~2–16 ohms depending on high- or low-impedance design — consult Audi spec
- Resting circuit voltage at injector power feed: battery voltage (approx. 12–14 V with key on/engine running)
- Injector driver ground switching: PCM pulls injector low to energize; expect ~0 V on switched side when energized
- Injector pulse width: varies with load; small at idle (~1–3 ms) and longer under load; observable with scope
- No short to battery: no sustained 12 V on driver side when injector should be open
Diagnostic algorithm
- Connect a scan tool, read stored/ pending DTCs and freeze frame; confirm P0203 and note any related codes (P0303, P0200, etc.).
- Visually inspect injector 3 connector and harness for corrosion, pin damage, heat or rodent damage; repair obvious issues.
- Verify battery voltage and check injector fuse/relay circuits for proper voltage at the injector power feed with ignition ON.
- With connector unplugged, measure injector 3 coil resistance and compare to spec. Abnormal open or short indicates bad injector.
- Back-probe the injector harness with the engine cranking or running: confirm PCM provides pulse (switches ground) and that power feed is present.
- Use an oscilloscope to view pulse waveform for distortions or stuck-on driver; if no pulse present but PCM commands it, suspect wiring/PCM.
- Perform continuity and short-to-power/ground checks between injector pin and PCM connector/pin; repair any harness faults.
- If injector resistance and wiring are good but driver signal abnormal, test by swapping injectors between cylinders. If code follows injector, replace injector.
- If code remains on original cylinder after swapping injectors, and wiring checks out, consider PCM injector driver fault — consult dealer-level diagnostics and repair procedures before replacing PCM.
- Clear codes and test drive; confirm repair by ensuring code does not return and engine runs normally.
Likely causes
- Damaged connector or pin corrosion at injector 3
- Wiring short to battery or short to ground in injector 3 circuit
- Injector 3 has failed internally (open coil or short)
- PCM driver for injector 3 has failed (less common)
- Low battery voltage or fuse/relay issue feeding injectors
Fault status
Status
Injector Circuit/Open — Cylinder 3 (P0203). PCM detected abnormal electrical condition on fuel injector circuit for cylinder 3; MIL on.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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