Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Self-Diagnostic System
Body Control Module (BCM) is equipped with a self-diagnostic system, which detects system Diagnostic Trouble Codes (DTCs) or abnormalities. When a malfunction occurs, BCM will store a DTC. See BCM DTC DEFINITIONS table. Malfunctions are recorded as history/intermittent failures or as current failures. Current DTCs indicate BCM has detected a fault which is currently present. A history DTC indicates that BCM has previously detected a malfunction that does not currently exist.
A scan tool can be used to retrieve and clear DTCs. Scan tool also has several features used to help locate an intermittent condition. When scan tool is used for system tests, it will display values actually seen or commanded by various systems (i.e., BCM, PCM). This will usually include the following types of information:
- Analog Data Input
Displays analog input seen by system. - Inputs/Outputs
Displays digital values as seen by system, and provides indication of whether input or output has cycled. - Special Functions (Output Controls)
Allows for outputs of system to be set at a desired value (ON or OFF). This will only indicate if BCM is sending appropriate commands, not what action was actually taken. - Clear Codes
Will erase DTCs for system currently selected (if problem still exists in system, DTC may immediately reset).
| DTC (1) | Description | ||||
|---|---|---|---|---|---|
| B0608 | BCM Power Malfunction | ||||
| B1000 | ECU Malfunction | ||||
| B1013 | Calibration ROM Checksum Error | ||||
| B1334 | Device Power No. 2 (Low Current) Circuit Open | ||||
| B1339 | Device Power No. 3 Circuit Open | ||||
| B1334 | Device Ground No. 2 (Chassis Ground No. 2) Circuit Open | ||||
| B1422 | BCM Power Malfunction | ||||
| B2947 (2) | Passlock(tm) Power (Shorted To Ground) | ||||
| B2948 (2) | Passlock(tm) Power (Shorted To Voltage) | ||||
| B2960 (2) | Passlock(tm) Data Incorrect | ||||
| B2957 (2) | Passlock(tm) Data Circuit Shorted To Ground | ||||
| B2958 (2) | Passlock(tm) Data Circuit Shorted To Voltage Or Open | ||||
| B3031 (2) | Passlock(tm) Programming Mode Active | ||||
| B3033 (2) | Passlock(tm) Indicates Tamper | ||||
| U1000 | Class 2 Serial Data Link Malfunction | ||||
| U1300 | Class 2 Data Link Shorted To Ground | ||||
| U1301 | Class 2 Data Link Shorted To Power | ||||
|
|||||
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
No obligation. See pricing before you book.