Code
C1225
Generic
C — Chassis
Lamp Brake Warning Output Circuit Short To Battery
Views:
UK: 19
EN: 41
RU: 26
AI status
Completed
Completed
100%
Causes
- Damaged or chafed wiring in the brake warning lamp output circuit creating a short to battery
- Corroded or bridged connector or socket at the instrument cluster or lamp assembly
- Failed brake-warn lamp bulb or LED driver internally shorted to battery
- Stuck/shorted relay or fused feed providing battery voltage to the output when it should be open
- Faulty body control module (BCM) / ABS module or internal driver transistor failure
- Aftermarket accessories improperly wired into the lighting circuit
Symptoms
- Brake warning lamp (and possibly related warning indicators) illuminated continuously
- Brake warning lamp does not respond to ignition or brake switch changes (stays on)
- Intermittent or constant battery drain in some cases
- Possible multiple related warning lamps if BCM shares circuits
What to check
- Retrieve freeze frame and stored codes from BCM/ABS/instrument cluster and note occurrence conditions
- Perform visual inspection of instrument cluster connector, fuse box, lamp sockets, and visible wiring harnesses for damage or corrosion
- Check for aftermarket devices connected to lighting or brake circuits
- With ignition ON, measure voltage at the brake-warn output pin at the controlling module and at the lamp connector
- Disconnect the lamp/cluster connector and see if code clears or voltage changes to isolate load vs driver issue
- Inspect and test related fuses and relays for stuck contacts
Signal parameters
- Expected: With circuit inactive, driver output should be open/low (approx. 0–1 V) or high-impedance; with lamp commanded ON it should present battery voltage (~11–14.5 V) through lamp load
- Fault present: steady battery voltage (~12 V) measured at the output when lamp should be OFF
- Typical lamp load: incandescent filaments show low resistance (~1–30 Ω depending on bulb); LED modules may show higher or electronic loads — consult vehicle wiring diagram
Diagnostic algorithm
- Read and record all stored codes and readiness status from BCM/ABS/instrument cluster.
- Reproduce fault if possible and note when it occurs (key position, braking, doors, unlock).
- Visually inspect wiring, connectors, and lamp sockets for damage, corrosion, or signs of shorting; repair as needed.
- Disconnect the brake-warn lamp connector at the instrument cluster or lamp assembly. Clear the code and cycle ignition. If the code does not return, the short is in the wiring or lamp assembly downstream of the connector.
- With connector disconnected and ignition ON, backprobe the module output pin. Measure voltage: if ~12 V with connector disconnected, the module output is being fed by battery (short) or the module driver has failed. If low/0 V with connector disconnected but rises when connector is attached, suspect lamp/connector or downstream short.
- Isolate wiring by disconnecting intermediate connectors or removing lamp sockets until the short is localized. Use a fused jumper or test light to prevent damage during checks.
- If wiring and lamp assembly are verified OK, replace or repair the controlling module per manufacturer procedure. Verify replacement resolves code.
- After repairs, clear codes and perform road/operation test to confirm the fault does not return.
Likely causes
- Shorted wiring or pin terminal at instrument cluster connector
- Corroded lamp socket or passenger compartment connector causing positive feed to appear on the output circuit
- Faulty instrument cluster/BCM output driver (replace only after wiring is verified)
- Bulb or LED module failure with internal short
Fault status
Status
Brake warning lamp output circuit short to battery detected — the output is seeing battery voltage when it should be off. Inspect wiring, connectors, lamp(s), and controlling module.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 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
C1225
HUMMER
C — Chassis
Left Front Excessive Wheel Speed Variation
Views:
UK: 13
EN: 25
RU: 16
AI status
Completed
Completed
100%
Causes
- Damaged or chafed wiring in the brake warning lamp output circuit creating a short to battery
- Corroded or bridged connector or socket at the instrument cluster or lamp assembly
- Failed brake-warn lamp bulb or LED driver internally shorted to battery
- Stuck/shorted relay or fused feed providing battery voltage to the output when it should be open
- Faulty body control module (BCM) / ABS module or internal driver transistor failure
- Aftermarket accessories improperly wired into the lighting circuit
Symptoms
- Brake warning lamp (and possibly related warning indicators) illuminated continuously
- Brake warning lamp does not respond to ignition or brake switch changes (stays on)
- Intermittent or constant battery drain in some cases
- Possible multiple related warning lamps if BCM shares circuits
What to check
- Retrieve freeze frame and stored codes from BCM/ABS/instrument cluster and note occurrence conditions
- Perform visual inspection of instrument cluster connector, fuse box, lamp sockets, and visible wiring harnesses for damage or corrosion
- Check for aftermarket devices connected to lighting or brake circuits
- With ignition ON, measure voltage at the brake-warn output pin at the controlling module and at the lamp connector
- Disconnect the lamp/cluster connector and see if code clears or voltage changes to isolate load vs driver issue
- Inspect and test related fuses and relays for stuck contacts
Signal parameters
- Expected: With circuit inactive, driver output should be open/low (approx. 0–1 V) or high-impedance; with lamp commanded ON it should present battery voltage (~11–14.5 V) through lamp load
- Fault present: steady battery voltage (~12 V) measured at the output when lamp should be OFF
- Typical lamp load: incandescent filaments show low resistance (~1–30 Ω depending on bulb); LED modules may show higher or electronic loads — consult vehicle wiring diagram
Diagnostic algorithm
- Read and record all stored codes and readiness status from BCM/ABS/instrument cluster.
- Reproduce fault if possible and note when it occurs (key position, braking, doors, unlock).
- Visually inspect wiring, connectors, and lamp sockets for damage, corrosion, or signs of shorting; repair as needed.
- Disconnect the brake-warn lamp connector at the instrument cluster or lamp assembly. Clear the code and cycle ignition. If the code does not return, the short is in the wiring or lamp assembly downstream of the connector.
- With connector disconnected and ignition ON, backprobe the module output pin. Measure voltage: if ~12 V with connector disconnected, the module output is being fed by battery (short) or the module driver has failed. If low/0 V with connector disconnected but rises when connector is attached, suspect lamp/connector or downstream short.
- Isolate wiring by disconnecting intermediate connectors or removing lamp sockets until the short is localized. Use a fused jumper or test light to prevent damage during checks.
- If wiring and lamp assembly are verified OK, replace or repair the controlling module per manufacturer procedure. Verify replacement resolves code.
- After repairs, clear codes and perform road/operation test to confirm the fault does not return.
Likely causes
- Shorted wiring or pin terminal at instrument cluster connector
- Corroded lamp socket or passenger compartment connector causing positive feed to appear on the output circuit
- Faulty instrument cluster/BCM output driver (replace only after wiring is verified)
- Bulb or LED module failure with internal short
Fault status
Status
Brake warning lamp output circuit short to battery detected — the output is seeing battery voltage when it should be off. Inspect wiring, connectors, lamp(s), and controlling module.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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Code
C1225
HYUNDAI
C — Chassis
ASC Potentiometer - Low Input
Views:
UK: 16
EN: 23
RU: 16
AI status
Completed
Completed
100%
Causes
- Damaged or chafed wiring in the brake warning lamp output circuit creating a short to battery
- Corroded or bridged connector or socket at the instrument cluster or lamp assembly
- Failed brake-warn lamp bulb or LED driver internally shorted to battery
- Stuck/shorted relay or fused feed providing battery voltage to the output when it should be open
- Faulty body control module (BCM) / ABS module or internal driver transistor failure
- Aftermarket accessories improperly wired into the lighting circuit
Symptoms
- Brake warning lamp (and possibly related warning indicators) illuminated continuously
- Brake warning lamp does not respond to ignition or brake switch changes (stays on)
- Intermittent or constant battery drain in some cases
- Possible multiple related warning lamps if BCM shares circuits
What to check
- Retrieve freeze frame and stored codes from BCM/ABS/instrument cluster and note occurrence conditions
- Perform visual inspection of instrument cluster connector, fuse box, lamp sockets, and visible wiring harnesses for damage or corrosion
- Check for aftermarket devices connected to lighting or brake circuits
- With ignition ON, measure voltage at the brake-warn output pin at the controlling module and at the lamp connector
- Disconnect the lamp/cluster connector and see if code clears or voltage changes to isolate load vs driver issue
- Inspect and test related fuses and relays for stuck contacts
Signal parameters
- Expected: With circuit inactive, driver output should be open/low (approx. 0–1 V) or high-impedance; with lamp commanded ON it should present battery voltage (~11–14.5 V) through lamp load
- Fault present: steady battery voltage (~12 V) measured at the output when lamp should be OFF
- Typical lamp load: incandescent filaments show low resistance (~1–30 Ω depending on bulb); LED modules may show higher or electronic loads — consult vehicle wiring diagram
Diagnostic algorithm
- Read and record all stored codes and readiness status from BCM/ABS/instrument cluster.
- Reproduce fault if possible and note when it occurs (key position, braking, doors, unlock).
- Visually inspect wiring, connectors, and lamp sockets for damage, corrosion, or signs of shorting; repair as needed.
- Disconnect the brake-warn lamp connector at the instrument cluster or lamp assembly. Clear the code and cycle ignition. If the code does not return, the short is in the wiring or lamp assembly downstream of the connector.
- With connector disconnected and ignition ON, backprobe the module output pin. Measure voltage: if ~12 V with connector disconnected, the module output is being fed by battery (short) or the module driver has failed. If low/0 V with connector disconnected but rises when connector is attached, suspect lamp/connector or downstream short.
- Isolate wiring by disconnecting intermediate connectors or removing lamp sockets until the short is localized. Use a fused jumper or test light to prevent damage during checks.
- If wiring and lamp assembly are verified OK, replace or repair the controlling module per manufacturer procedure. Verify replacement resolves code.
- After repairs, clear codes and perform road/operation test to confirm the fault does not return.
Likely causes
- Shorted wiring or pin terminal at instrument cluster connector
- Corroded lamp socket or passenger compartment connector causing positive feed to appear on the output circuit
- Faulty instrument cluster/BCM output driver (replace only after wiring is verified)
- Bulb or LED module failure with internal short
Fault status
Status
Brake warning lamp output circuit short to battery detected — the output is seeing battery voltage when it should be off. Inspect wiring, connectors, lamp(s), and controlling module.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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0
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0
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Code
C1225
MITSUBISHI
C — Chassis
Deviation between wheel speed
Views:
UK: 10
EN: 19
RU: 13
AI status
Completed
Completed
100%
Causes
- Damaged or chafed wiring in the brake warning lamp output circuit creating a short to battery
- Corroded or bridged connector or socket at the instrument cluster or lamp assembly
- Failed brake-warn lamp bulb or LED driver internally shorted to battery
- Stuck/shorted relay or fused feed providing battery voltage to the output when it should be open
- Faulty body control module (BCM) / ABS module or internal driver transistor failure
- Aftermarket accessories improperly wired into the lighting circuit
Symptoms
- Brake warning lamp (and possibly related warning indicators) illuminated continuously
- Brake warning lamp does not respond to ignition or brake switch changes (stays on)
- Intermittent or constant battery drain in some cases
- Possible multiple related warning lamps if BCM shares circuits
What to check
- Retrieve freeze frame and stored codes from BCM/ABS/instrument cluster and note occurrence conditions
- Perform visual inspection of instrument cluster connector, fuse box, lamp sockets, and visible wiring harnesses for damage or corrosion
- Check for aftermarket devices connected to lighting or brake circuits
- With ignition ON, measure voltage at the brake-warn output pin at the controlling module and at the lamp connector
- Disconnect the lamp/cluster connector and see if code clears or voltage changes to isolate load vs driver issue
- Inspect and test related fuses and relays for stuck contacts
Signal parameters
- Expected: With circuit inactive, driver output should be open/low (approx. 0–1 V) or high-impedance; with lamp commanded ON it should present battery voltage (~11–14.5 V) through lamp load
- Fault present: steady battery voltage (~12 V) measured at the output when lamp should be OFF
- Typical lamp load: incandescent filaments show low resistance (~1–30 Ω depending on bulb); LED modules may show higher or electronic loads — consult vehicle wiring diagram
Diagnostic algorithm
- Read and record all stored codes and readiness status from BCM/ABS/instrument cluster.
- Reproduce fault if possible and note when it occurs (key position, braking, doors, unlock).
- Visually inspect wiring, connectors, and lamp sockets for damage, corrosion, or signs of shorting; repair as needed.
- Disconnect the brake-warn lamp connector at the instrument cluster or lamp assembly. Clear the code and cycle ignition. If the code does not return, the short is in the wiring or lamp assembly downstream of the connector.
- With connector disconnected and ignition ON, backprobe the module output pin. Measure voltage: if ~12 V with connector disconnected, the module output is being fed by battery (short) or the module driver has failed. If low/0 V with connector disconnected but rises when connector is attached, suspect lamp/connector or downstream short.
- Isolate wiring by disconnecting intermediate connectors or removing lamp sockets until the short is localized. Use a fused jumper or test light to prevent damage during checks.
- If wiring and lamp assembly are verified OK, replace or repair the controlling module per manufacturer procedure. Verify replacement resolves code.
- After repairs, clear codes and perform road/operation test to confirm the fault does not return.
Likely causes
- Shorted wiring or pin terminal at instrument cluster connector
- Corroded lamp socket or passenger compartment connector causing positive feed to appear on the output circuit
- Faulty instrument cluster/BCM output driver (replace only after wiring is verified)
- Bulb or LED module failure with internal short
Fault status
Status
Brake warning lamp output circuit short to battery detected — the output is seeing battery voltage when it should be off. Inspect wiring, connectors, lamp(s), and controlling module.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
C1225
Other
C — Chassis
Lamp Brake Warning Output Circuit Short To Battery
Views:
UK: 24
EN: 37
RU: 33
AI status
Completed
Completed
100%
Causes
- Damaged or chafed wiring in the brake warning lamp output circuit creating a short to battery
- Corroded or bridged connector or socket at the instrument cluster or lamp assembly
- Failed brake-warn lamp bulb or LED driver internally shorted to battery
- Stuck/shorted relay or fused feed providing battery voltage to the output when it should be open
- Faulty body control module (BCM) / ABS module or internal driver transistor failure
- Aftermarket accessories improperly wired into the lighting circuit
Symptoms
- Brake warning lamp (and possibly related warning indicators) illuminated continuously
- Brake warning lamp does not respond to ignition or brake switch changes (stays on)
- Intermittent or constant battery drain in some cases
- Possible multiple related warning lamps if BCM shares circuits
What to check
- Retrieve freeze frame and stored codes from BCM/ABS/instrument cluster and note occurrence conditions
- Perform visual inspection of instrument cluster connector, fuse box, lamp sockets, and visible wiring harnesses for damage or corrosion
- Check for aftermarket devices connected to lighting or brake circuits
- With ignition ON, measure voltage at the brake-warn output pin at the controlling module and at the lamp connector
- Disconnect the lamp/cluster connector and see if code clears or voltage changes to isolate load vs driver issue
- Inspect and test related fuses and relays for stuck contacts
Signal parameters
- Expected: With circuit inactive, driver output should be open/low (approx. 0–1 V) or high-impedance; with lamp commanded ON it should present battery voltage (~11–14.5 V) through lamp load
- Fault present: steady battery voltage (~12 V) measured at the output when lamp should be OFF
- Typical lamp load: incandescent filaments show low resistance (~1–30 Ω depending on bulb); LED modules may show higher or electronic loads — consult vehicle wiring diagram
Diagnostic algorithm
- Read and record all stored codes and readiness status from BCM/ABS/instrument cluster.
- Reproduce fault if possible and note when it occurs (key position, braking, doors, unlock).
- Visually inspect wiring, connectors, and lamp sockets for damage, corrosion, or signs of shorting; repair as needed.
- Disconnect the brake-warn lamp connector at the instrument cluster or lamp assembly. Clear the code and cycle ignition. If the code does not return, the short is in the wiring or lamp assembly downstream of the connector.
- With connector disconnected and ignition ON, backprobe the module output pin. Measure voltage: if ~12 V with connector disconnected, the module output is being fed by battery (short) or the module driver has failed. If low/0 V with connector disconnected but rises when connector is attached, suspect lamp/connector or downstream short.
- Isolate wiring by disconnecting intermediate connectors or removing lamp sockets until the short is localized. Use a fused jumper or test light to prevent damage during checks.
- If wiring and lamp assembly are verified OK, replace or repair the controlling module per manufacturer procedure. Verify replacement resolves code.
- After repairs, clear codes and perform road/operation test to confirm the fault does not return.
Likely causes
- Shorted wiring or pin terminal at instrument cluster connector
- Corroded lamp socket or passenger compartment connector causing positive feed to appear on the output circuit
- Faulty instrument cluster/BCM output driver (replace only after wiring is verified)
- Bulb or LED module failure with internal short
Fault status
Status
Brake warning lamp output circuit short to battery detected — the output is seeing battery voltage when it should be off. Inspect wiring, connectors, lamp(s), and controlling module.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 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
+100 karma for a short comment :)
Was this AI description helpful?
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