What Does B1302 Mean?
This code indicates the Body Control Module (BCM) has detected an electrical fault in the accessory delay relay coil circuit. The accessory delay relay allows certain vehicle accessories (radio, power windows, etc.) to remain operational for a set time after the ignition is turned off. The BCM has detected an open circuit, short circuit, or excessive resistance in the relay coil control circuit that prevents proper relay activation.
Common Causes
45%
Failed accessory delay relay with open or shorted coil windings
30%
Damaged wiring or corroded connector at relay control circuit
15%
Blown fuse or poor connection in relay control power supply circuit
10%
Failed Body Control Module internal relay driver circuit
Diagnostic Steps
1
Step 1: Locate the accessory delay relay (typically in underhood fuse/relay box or interior junction box) and visually inspect for physical damage, corrosion, or burnt terminals. Remove relay and check socket for damage, corrosion, or debris.
2
Step 2: Using a digital multimeter, measure the resistance across the relay coil terminals (typically pins 85 and 86). Normal reading should be 70-120 ohms depending on relay type. Infinite resistance indicates open coil; zero resistance indicates short.
3
Step 3: Check for power and ground at the relay socket with key on. Verify battery voltage at the power supply terminal and good ground at the ground terminal. Check the control signal wire from BCM for proper voltage drop when relay should activate (typically switching from 12V to ground).
4
Step 4: Inspect the wiring harness between relay socket and BCM for chafing, pinching, or damage. Check all connector pins for corrosion, spread terminals, or pushed-back pins. Perform continuity test on control circuit wire from relay socket to BCM connector.
5
Step 5: If all wiring and connections test good but relay fails resistance test, replace the accessory delay relay. If relay tests good but control signal is absent, suspect BCM fault. Clear codes and verify proper accessory delay function after repair.
Estimated Repair Cost
$75 - $400
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected an electrical fault in the accessory delay relay coil circuit. The accessory delay relay allows certain vehicle accessories (radio, power windows, etc.) to remain operational for a set time after the ignition is turned off. The BCM has d...
The most common cause of B1302 (Accessory Delay Relay Coil Circuit Failure) is: Failed accessory delay relay with open or shorted coil windings
Typical repair costs for B1302 range from $75 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving as this does not affect critical vehicle operation. Accessories may not remain powered after key-off, which is an inconvenience but not a safety hazard. Repair at your earliest convenience.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1302 to identify the root cause.
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Quick Info
Category
Body
System
Body Control / Accessory Power Management
Difficulty
Type
Manufacturer
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