Code
B0235
Generic
B — Body
Left Front Door Lock Circuit Short to Ground
AI status
Completed
Completed
100%
Causes
- Damaged wiring harness (chafing, pinched) to left front door lock actuator
- Corroded or pushed-out connector terminals at door or body harness
- Failed left front door lock actuator with internal short
- Shorted control module driver (BCM/body control module)
- Water intrusion in door or connector causing low resistance to ground
- Aftermarket alarm/remote wiring incorrectly connected
Symptoms
- Left front door lock does not operate (won't lock or unlock)
- Intermittent locking/unlocking of left front door
- Blown fuse related to door locks or elevated current draw
- Other door modules report communication errors (occasionally)
- Burnt smell near door harness or connector in severe shorts
What to check
- Scan for active and stored DTCs; note freeze frame and related codes
- Inspect left front door wiring along the hinge/jamb for damage or pinching
- Visually and mechanically inspect connectors at the door and body harness
- Check door lock fuse and related relays for damage or signs of overheating
- Measure resistance/continuity between the lock output pin and chassis ground with connector disconnected
- Back-probe the lock actuator connector while operating the lock to observe voltage and polarity
Signal parameters
- Battery voltage (nominal): 12.0–14.5 V on supply circuits
- Actuator coil resistance (typical): 5–50 ohms depending on design — consult vehicle spec
- Expected driver output when commanded: switches between battery voltage and ground (polarity reversal) or supplies a PWM drive; measured voltage change should correspond to command
- Short-to-ground condition: low resistance (
- Current draw during operation: normally under several amps; excessive current (>5–10 A) suggests short or seized actuator (check vehicle spec)
Diagnostic algorithm
- Retrieve freeze frame and history of B0235, check for related door or body codes.
- Visually inspect door hinge area harness for abrasion, broken insulation, or paint-through spots where wires flex. Repair any damaged wiring using proper splices/protection.
- With ignition off, disconnect the left front door lock actuator connector. Measure resistance between the suspected BCM output pin and chassis ground. Resistance near zero indicates a short to ground in harness or actuator.
- If resistance is high/normal with connector disconnected, back-probe the connector at the body harness side and operate the lock while monitoring voltage. Verify expected voltage/polarity changes. No change or stuck at ground suggests module driver fault.
- If the harness side shows normal behavior but the actuator side does not, test actuator directly by applying fused 12 V briefly (observe polarity and current). Replace actuator if it draws excessive current or does not operate.
- Inspect and clean connectors; repair corroded terminals or replace connector halves and rubber seals as needed. Re-test after repairs.
- If wiring and actuator check good, perform module output driver test per manufacturer procedure (may require oscilloscope or specialized tool). Replace/control module only after confirming driver failure.
- After repair, clear codes and perform multiple lock/unlock cycles to confirm DTC does not return. Document repairs and advise customer of any recurring or intermittent wiring issues.
Likely causes
- Chafed or pinched wire where the door harness bends (most common)
- Corroded/mis-seated connector at door jamb or inside door
- Failed actuator motor or internal short
- Body control module output driver fault
- Water or debris inside connector causing a ground path
Fault status
Status
Short to ground detected on Left Front Door Lock Circuit — module has set B0235.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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