Code
B1440
HUMMER
B — Body
Power Mode Master Input Circuits Mismatch
Views:
UK: 7
EN: 10
RU: 8
AI status
Completed
Completed
100%
Causes
- Damaged or shorted wiring harness between ignition/power mode switch and vehicle modules
- Poor or intermittent connector contact (corrosion, bent pins, loose terminals)
- Faulty ignition switch / power mode selector (mechanical or electrical failure)
- Faulty body control module (BCM) or instrument cluster reporting power mode
- Low battery voltage or intermittent battery/ground connection
- Software/configuration mismatch or module needing reflash
Symptoms
- Malfunction of key-on/accessory functions (radio, windows, HVAC)
- No-crank or intermittent crank/no-start related to power mode
- Illumination of dash warning lamp(s) and stored B1440
- Unresponsive or inconsistent ignition key positions (ACC/RUN/START)
- Erratic accessory behavior or modules reverting to default/safe mode
What to check
- Scan for B1440 and any stored/related codes (U-codes, B-codes, P-codes)
- Verify battery voltage is healthy (12.4–12.8 V at rest, >13.5 V with engine running)
- Inspect connectors and wiring at the ignition/power mode switch, BCM, and IPC
- Backprobe power mode signal circuits and monitor while cycling key positions
- Check for CAN/LIN errors or modules reporting lost communication
- Perform wiggle test on harness while monitoring signal and code status
Signal parameters
- Power mode signal expected states: OFF, ACC, RUN (IGN), START — verify correct state transitions when key operated
- Voltage on power mode feed: near battery voltage (~12 V) when asserted, ~0 V when not; some inputs are low-side switched or pull-ups — consult wiring diagram
- Digital/logic inputs may be switched to ground or to ignition voltage; open circuits or intermediate voltages indicate wiring/connector issues
- CAN/LIN bus messages: modules should publish consistent power mode status; check for missing or conflicting messages
Diagnostic algorithm
- Retrieve all DTCs and freeze frame data. Note any communication (U0xxx) or voltage (P0562) codes.
- Verify battery condition and charge if needed. Clear codes and attempt to reproduce with a fully charged battery.
- Visually inspect connectors and wiring for damage, corrosion, or pin distortion at ignition switch, BCM, and instrument cluster.
- Backprobe the power mode input circuits at the switch and at the receiving module(s). With a DVOM or scope, observe signal behavior across OFF/ACC/RUN/START. Look for missing transitions, intermittent, or contradictory states between modules.
- If signals are incorrect at the module but correct at the switch, trace and repair wiring/connectors between switch and module. If signals are incorrect at the switch, test/replace the ignition/power mode switch.
- Monitor CAN/LIN communications with a scan tool to ensure modules are broadcasting and receiving power mode messages consistently. Repair bus faults (terminations, shorts) if present.
- If wiring and switch check good and communication is stable, check for module software updates or configuration errors. Reflash or reprogram BCM/IPC as per manufacturer service information.
- Replace the affected module only after confirming a hardware failure; verify repair by clearing codes and performing a full function test across multiple key cycles.
Likely causes
- Loose or corroded connector at ignition switch or BCM
- Open or shorted signal wire between ignition switch and BCM/IPC
- Faulty ignition switch that fails to assert expected voltage in a key position
- Module communication failure (BCM or cluster) or lost CAN messages
Fault status
Status
Power Mode Master input circuits report inconsistent or invalid states between modules; vehicle modules disagree on ignition/power mode.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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Code
B1440
LAND ROVER
B — Body
Windshield wiper mode selection switch - short circuit for battery
Views:
UK: 6
EN: 8
RU: 7
AI status
Completed
Completed
100%
Causes
- Damaged or shorted wiring harness between ignition/power mode switch and vehicle modules
- Poor or intermittent connector contact (corrosion, bent pins, loose terminals)
- Faulty ignition switch / power mode selector (mechanical or electrical failure)
- Faulty body control module (BCM) or instrument cluster reporting power mode
- Low battery voltage or intermittent battery/ground connection
- Software/configuration mismatch or module needing reflash
Symptoms
- Malfunction of key-on/accessory functions (radio, windows, HVAC)
- No-crank or intermittent crank/no-start related to power mode
- Illumination of dash warning lamp(s) and stored B1440
- Unresponsive or inconsistent ignition key positions (ACC/RUN/START)
- Erratic accessory behavior or modules reverting to default/safe mode
What to check
- Scan for B1440 and any stored/related codes (U-codes, B-codes, P-codes)
- Verify battery voltage is healthy (12.4–12.8 V at rest, >13.5 V with engine running)
- Inspect connectors and wiring at the ignition/power mode switch, BCM, and IPC
- Backprobe power mode signal circuits and monitor while cycling key positions
- Check for CAN/LIN errors or modules reporting lost communication
- Perform wiggle test on harness while monitoring signal and code status
Signal parameters
- Power mode signal expected states: OFF, ACC, RUN (IGN), START — verify correct state transitions when key operated
- Voltage on power mode feed: near battery voltage (~12 V) when asserted, ~0 V when not; some inputs are low-side switched or pull-ups — consult wiring diagram
- Digital/logic inputs may be switched to ground or to ignition voltage; open circuits or intermediate voltages indicate wiring/connector issues
- CAN/LIN bus messages: modules should publish consistent power mode status; check for missing or conflicting messages
Diagnostic algorithm
- Retrieve all DTCs and freeze frame data. Note any communication (U0xxx) or voltage (P0562) codes.
- Verify battery condition and charge if needed. Clear codes and attempt to reproduce with a fully charged battery.
- Visually inspect connectors and wiring for damage, corrosion, or pin distortion at ignition switch, BCM, and instrument cluster.
- Backprobe the power mode input circuits at the switch and at the receiving module(s). With a DVOM or scope, observe signal behavior across OFF/ACC/RUN/START. Look for missing transitions, intermittent, or contradictory states between modules.
- If signals are incorrect at the module but correct at the switch, trace and repair wiring/connectors between switch and module. If signals are incorrect at the switch, test/replace the ignition/power mode switch.
- Monitor CAN/LIN communications with a scan tool to ensure modules are broadcasting and receiving power mode messages consistently. Repair bus faults (terminations, shorts) if present.
- If wiring and switch check good and communication is stable, check for module software updates or configuration errors. Reflash or reprogram BCM/IPC as per manufacturer service information.
- Replace the affected module only after confirming a hardware failure; verify repair by clearing codes and performing a full function test across multiple key cycles.
Likely causes
- Loose or corroded connector at ignition switch or BCM
- Open or shorted signal wire between ignition switch and BCM/IPC
- Faulty ignition switch that fails to assert expected voltage in a key position
- Module communication failure (BCM or cluster) or lost CAN messages
Fault status
Status
Power Mode Master input circuits report inconsistent or invalid states between modules; vehicle modules disagree on ignition/power mode.
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
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Code
B1440
MITSUBISHI
B — Body
FR curtain ABG squib short
Views:
UK: 8
EN: 10
RU: 8
AI status
Completed
Completed
100%
Causes
- Damaged or shorted wiring harness between ignition/power mode switch and vehicle modules
- Poor or intermittent connector contact (corrosion, bent pins, loose terminals)
- Faulty ignition switch / power mode selector (mechanical or electrical failure)
- Faulty body control module (BCM) or instrument cluster reporting power mode
- Low battery voltage or intermittent battery/ground connection
- Software/configuration mismatch or module needing reflash
Symptoms
- Malfunction of key-on/accessory functions (radio, windows, HVAC)
- No-crank or intermittent crank/no-start related to power mode
- Illumination of dash warning lamp(s) and stored B1440
- Unresponsive or inconsistent ignition key positions (ACC/RUN/START)
- Erratic accessory behavior or modules reverting to default/safe mode
What to check
- Scan for B1440 and any stored/related codes (U-codes, B-codes, P-codes)
- Verify battery voltage is healthy (12.4–12.8 V at rest, >13.5 V with engine running)
- Inspect connectors and wiring at the ignition/power mode switch, BCM, and IPC
- Backprobe power mode signal circuits and monitor while cycling key positions
- Check for CAN/LIN errors or modules reporting lost communication
- Perform wiggle test on harness while monitoring signal and code status
Signal parameters
- Power mode signal expected states: OFF, ACC, RUN (IGN), START — verify correct state transitions when key operated
- Voltage on power mode feed: near battery voltage (~12 V) when asserted, ~0 V when not; some inputs are low-side switched or pull-ups — consult wiring diagram
- Digital/logic inputs may be switched to ground or to ignition voltage; open circuits or intermediate voltages indicate wiring/connector issues
- CAN/LIN bus messages: modules should publish consistent power mode status; check for missing or conflicting messages
Diagnostic algorithm
- Retrieve all DTCs and freeze frame data. Note any communication (U0xxx) or voltage (P0562) codes.
- Verify battery condition and charge if needed. Clear codes and attempt to reproduce with a fully charged battery.
- Visually inspect connectors and wiring for damage, corrosion, or pin distortion at ignition switch, BCM, and instrument cluster.
- Backprobe the power mode input circuits at the switch and at the receiving module(s). With a DVOM or scope, observe signal behavior across OFF/ACC/RUN/START. Look for missing transitions, intermittent, or contradictory states between modules.
- If signals are incorrect at the module but correct at the switch, trace and repair wiring/connectors between switch and module. If signals are incorrect at the switch, test/replace the ignition/power mode switch.
- Monitor CAN/LIN communications with a scan tool to ensure modules are broadcasting and receiving power mode messages consistently. Repair bus faults (terminations, shorts) if present.
- If wiring and switch check good and communication is stable, check for module software updates or configuration errors. Reflash or reprogram BCM/IPC as per manufacturer service information.
- Replace the affected module only after confirming a hardware failure; verify repair by clearing codes and performing a full function test across multiple key cycles.
Likely causes
- Loose or corroded connector at ignition switch or BCM
- Open or shorted signal wire between ignition switch and BCM/IPC
- Faulty ignition switch that fails to assert expected voltage in a key position
- Module communication failure (BCM or cluster) or lost CAN messages
Fault status
Status
Power Mode Master input circuits report inconsistent or invalid states between modules; vehicle modules disagree on ignition/power mode.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
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👍 Like
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0
Send to email
Code
B1440
Other
B — Body
Wiper Mode Select Switch Circuit Short To Battery
Views:
UK: 18
EN: 28
RU: 16
AI status
Completed
Completed
100%
Causes
- Damaged or shorted wiring harness between ignition/power mode switch and vehicle modules
- Poor or intermittent connector contact (corrosion, bent pins, loose terminals)
- Faulty ignition switch / power mode selector (mechanical or electrical failure)
- Faulty body control module (BCM) or instrument cluster reporting power mode
- Low battery voltage or intermittent battery/ground connection
- Software/configuration mismatch or module needing reflash
Symptoms
- Malfunction of key-on/accessory functions (radio, windows, HVAC)
- No-crank or intermittent crank/no-start related to power mode
- Illumination of dash warning lamp(s) and stored B1440
- Unresponsive or inconsistent ignition key positions (ACC/RUN/START)
- Erratic accessory behavior or modules reverting to default/safe mode
What to check
- Scan for B1440 and any stored/related codes (U-codes, B-codes, P-codes)
- Verify battery voltage is healthy (12.4–12.8 V at rest, >13.5 V with engine running)
- Inspect connectors and wiring at the ignition/power mode switch, BCM, and IPC
- Backprobe power mode signal circuits and monitor while cycling key positions
- Check for CAN/LIN errors or modules reporting lost communication
- Perform wiggle test on harness while monitoring signal and code status
Signal parameters
- Power mode signal expected states: OFF, ACC, RUN (IGN), START — verify correct state transitions when key operated
- Voltage on power mode feed: near battery voltage (~12 V) when asserted, ~0 V when not; some inputs are low-side switched or pull-ups — consult wiring diagram
- Digital/logic inputs may be switched to ground or to ignition voltage; open circuits or intermediate voltages indicate wiring/connector issues
- CAN/LIN bus messages: modules should publish consistent power mode status; check for missing or conflicting messages
Diagnostic algorithm
- Retrieve all DTCs and freeze frame data. Note any communication (U0xxx) or voltage (P0562) codes.
- Verify battery condition and charge if needed. Clear codes and attempt to reproduce with a fully charged battery.
- Visually inspect connectors and wiring for damage, corrosion, or pin distortion at ignition switch, BCM, and instrument cluster.
- Backprobe the power mode input circuits at the switch and at the receiving module(s). With a DVOM or scope, observe signal behavior across OFF/ACC/RUN/START. Look for missing transitions, intermittent, or contradictory states between modules.
- If signals are incorrect at the module but correct at the switch, trace and repair wiring/connectors between switch and module. If signals are incorrect at the switch, test/replace the ignition/power mode switch.
- Monitor CAN/LIN communications with a scan tool to ensure modules are broadcasting and receiving power mode messages consistently. Repair bus faults (terminations, shorts) if present.
- If wiring and switch check good and communication is stable, check for module software updates or configuration errors. Reflash or reprogram BCM/IPC as per manufacturer service information.
- Replace the affected module only after confirming a hardware failure; verify repair by clearing codes and performing a full function test across multiple key cycles.
Likely causes
- Loose or corroded connector at ignition switch or BCM
- Open or shorted signal wire between ignition switch and BCM/IPC
- Faulty ignition switch that fails to assert expected voltage in a key position
- Module communication failure (BCM or cluster) or lost CAN messages
Fault status
Status
Power Mode Master input circuits report inconsistent or invalid states between modules; vehicle modules disagree on ignition/power mode.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
Workshop Manuals
Available brands with manuals
2
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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 :)
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