What Does B1333 Mean?
This code indicates the Body Control Module (BCM) has detected a short to battery voltage in the decklid or rear door ajar switch circuit. The BCM continuously monitors the state of the decklid/rear door ajar sensor, and when the circuit voltage reads higher than expected (typically battery voltage instead of ground or reference voltage), it sets this fault code. This results in the BCM receiving a constant 'door open' signal even when the door/decklid is closed.
Common Causes
45%
Damaged or chafed wiring harness causing short to power, particularly at hinges or body flex points
30%
Faulty decklid or rear door ajar switch with internal short to voltage
15%
Water intrusion or corrosion in switch connector causing cross-circuit contamination
10%
Failed Body Control Module with internal circuit fault
Diagnostic Steps
1
Step 1: Visually inspect the decklid/rear door ajar switch and connector for physical damage, water intrusion, corrosion, or melted terminals. Check wiring harness routing through hinge areas and door jambs for chafing or pinching against metal edges.
2
Step 2: Disconnect the decklid/rear door ajar switch connector. Using a digital multimeter, measure voltage on the BCM side of the circuit with ignition on. Reading should be approximately 0-5V reference voltage, not battery voltage (12V+). If battery voltage is present with switch disconnected, wiring has a short to power.
3
Step 3: Perform continuity test on the ajar switch circuit from the switch connector to BCM connector with all power disconnected. Wiggle harness at flex points while monitoring for intermittent shorts. Measure resistance between the ajar circuit wire and known power sources (fuse box, other circuits) to locate short point.
4
Step 4: If wiring tests normal, test the ajar switch itself by measuring resistance across terminals in both open and closed positions per manufacturer specifications. Replace switch if internal short is detected or readings are out of specification.
5
Step 5: Clear codes, reconnect all components, cycle decklid/door open and closed multiple times while monitoring live data for proper state changes. Verify interior lights, warning chimes, and door ajar indicators function correctly without false activation.
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected a short to battery voltage in the decklid or rear door ajar switch circuit. The BCM continuously monitors the state of the decklid/rear door ajar sensor, and when the circuit voltage reads higher than expected (typically battery voltage ...
The most common cause of B1333 (Decklid Ajar Rear Door Circuit Short To Battery) is: Damaged or chafed wiring harness causing short to power, particularly at hinges or body flex points
Typical repair costs for B1333 range from $75 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving. This fault primarily causes nuisance symptoms such as interior lights staying on, false door ajar warnings, and potential battery drain if lights remain illuminated for extended periods. No immediate safety risk, but should be repaired to prevent battery discharge.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1333 to identify the root cause.
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Quick Info
Category
Body
System
Body Control and Door/Decklid Monitoring System
Difficulty
Type
Manufacturer
Recommended Tools
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