B1335

What Does Code B1335 Mean?

DTC B1335 signifies a “Rear Right Door Ajar Circuit Failure.” This diagnostic trouble code is typically generated by the Body Control Module (BCM), or in some vehicle architectures, directly by the Powertrain Control Module (PCM) or Instrument Cluster, which monitors the electrical integrity of the rear right door ajar switch circuit. The door ajar switch provides feedback to the vehicle’s control systems regarding the open or closed state of the door. When the BCM detects an unexpected electrical condition on this circuit—such as a continuous open circuit, a short to ground, or a short to voltage—that deviates from the expected parameters for a properly functioning switch and wiring, it sets code B1335.

This failure indicates that the control module cannot accurately determine the state of the rear right door, leading to potential malfunctions in related systems that rely on this input, including interior lighting, warning chimes, security systems, and central locking logic. The circuit failure implies an electrical fault within the wiring or the switch itself, rather than a mere mechanical state discrepancy (e.g., a legitimately open door).

Common Symptoms

• “Door Ajar” Warning Light: The rear right door ajar warning light or message may be continuously illuminated on the instrument cluster, even when the door is securely closed.
• Interior Lighting Issues: Interior dome lights may remain on constantly, drain the battery, or fail to illuminate when the rear right door is genuinely opened.
• Warning Chimes: A continuous or intermittent door ajar chime may sound while driving, despite the door being closed.
• Security System Malfunctions: The vehicle’s alarm system may be unable to arm, or it may trigger false alarms, as it incorrectly perceives an open door.
• Central Locking Problems: The power door locks may fail to lock all doors, or the doors may immediately unlock after being locked, due to the system’s belief that a door is still open.
• Battery Drain: If interior lights remain on due to the perceived open door, this can lead to accelerated battery discharge.

What Causes the Code B1335?

• Faulty Rear Right Door Ajar Switch: The switch itself can fail internally, becoming stuck in an open or closed position electrically, or developing high internal resistance.
• Damaged Wiring Harness:
  • Open Circuit: A break in the wire running from the door ajar switch to the BCM, often occurring in the flexible conduit between the door and the body due to repeated opening and closing cycles.
  • Short to Ground: The signal wire for the door ajar switch contacting the vehicle’s chassis ground, leading to an incorrect signal.
  • Short to Voltage: The signal wire inadvertently contacting a power source, sending an incorrect voltage signal to the BCM.
• Corrosion: Electrical corrosion at the door ajar switch connector, the BCM connector, or any in-line connectors within the circuit can lead to high resistance or intermittent signal loss.
• Faulty Body Control Module (BCM): Although less common, the input circuit within the BCM responsible for monitoring the rear right door ajar switch can develop an internal fault.
• Physical Damage or Misalignment: Severe impact damage to the door or a significant misalignment that physically damages or prevents the proper operation of the door ajar switch (though typically this would set a “door open” state rather than a “circuit failure” unless the switch is compromised).

How to Diagnose and Troubleshoot

Diagnosing B1335 requires a systematic approach, focusing on electrical integrity:

1. Preliminary Inspection and OBD-II Scan:
   • Connect an OBD-II scanner and retrieve all stored and pending DTCs. Note if B1335 is a current fault or a historic one.
   • Observe live data related to door status, if available on your scanner. Manually open and close the rear right door while monitoring the “rear right door ajar” parameter. Does it change states reliably?
   • Visually inspect the rear right door and its jamb for any obvious signs of damage, loose wiring, or obstructions that might affect the switch’s operation.
2. Locate and Access the Door Ajar Switch:
   • Consult the vehicle’s service manual to accurately locate the rear right door ajar switch. It is commonly integrated into the door latch assembly or mounted within the door jamb.
   • Carefully disconnect the electrical connector from the switch.
3. Test the Wiring Harness (at the switch connector):
   • Using a Digital Multimeter (DMM), identify the power, signal, and ground wires at the disconnected switch connector, referencing the vehicle’s wiring diagrams.
   • Power Supply Check: With the ignition ON, check for the specified voltage (e.g., 12V or 5V) at the power supply wire (if the switch is a voltage-sending type).
   • Ground Circuit Check: Check for good continuity (low resistance, typically < 5 ohms) to chassis ground on the ground wire (if applicable).
   • Signal Wire Check:
     • If the switch provides a ground signal to the BCM: Check the signal wire for battery voltage when the switch is disconnected. A reading close to 0V would indicate a short to ground in the wiring harness.
     • If the switch provides a voltage signal to the BCM: Check the signal wire for an open circuit or a specific voltage (e.g., 0V) when disconnected, depending on the BCM’s pull-up/pull-down resistor configuration.
   • Wiggle Test: While monitoring the DMM readings on the signal wire, gently wiggle the wiring harness, particularly where it passes through the door jamb. Look for any intermittent changes in voltage or continuity that would indicate a damaged wire.
4. Test the Door Ajar Switch (Standalone):
   • If possible, remove the door ajar switch for bench testing, or test it in situ if accessible.
   • Using the DMM set to continuity or resistance mode, manually actuate the switch (simulate opening and closing the door).
   • Verify that the switch reliably changes state. For a typical normally open switch, it should show infinite resistance (open circuit) when released and near 0 ohms (closed circuit) when depressed. For a normally closed switch, the opposite should be true.
5. BCM Input Verification (Advanced, If Necessary):
   • If the wiring and switch test good, the fault might lie within the BCM. Access the BCM connector and, using vehicle-specific wiring diagrams, back-probe the pin corresponding to the rear right door ajar input.
   • Monitor the voltage signal at this BCM pin while manually opening and closing the rear right door. Compare the observed signal states to the expected values specified in the service manual. Consistent incorrect readings here, despite good external wiring and switch, point to an internal BCM issue.

Recommended Repairs and Solutions

Based on the diagnostic findings, the following repairs are typically recommended:

• Replace the Rear Right Door Ajar Switch: If the switch tests faulty, replacement is the most common and straightforward solution. Always use a high-quality OEM or equivalent aftermarket switch to ensure proper fitment and reliable operation.
• Repair or Replace Damaged Wiring:
  • Open/Short Circuits: If diagnostic steps reveal a broken wire or a short to ground/voltage, meticulously inspect the entire length of the harness from the switch to the BCM. Pay close attention to the flexible boot in the door jamb. Repair damaged wires by soldering and heat-shrinking, or replace the entire affected section of the wiring harness if damage is extensive.
  • Corrosion: Clean any corroded connectors with electrical contact cleaner and apply dielectric grease to prevent future corrosion. If pins are severely corroded, replace the connector and corresponding terminals.
• Address Door Alignment: If the door’s alignment is significantly off, and it has caused physical damage or improper engagement of the switch, correct the door alignment (adjusting hinges or striker) after replacing the faulty switch.
• Body Control Module (BCM) Replacement: Only consider BCM replacement as a last resort, after thoroughly ruling out all other possibilities with the switch and wiring. BCM replacement typically requires specialized programming and calibration using an OEM-level diagnostic tool, often performed by a dealership or a qualified automotive electronics specialist.
• Post-Repair Verification: After completing any repair, clear the DTCs from the BCM using an OBD-II scanner. Operate the rear right door multiple times and perform a test drive to ensure the code does not return and that all associated functions (interior lights, chimes, security system) operate as intended.