Lost Communication with Powertrain Control Module B
A second powertrain control module (e.g. on dual-engine, twin-turbo bank-specific or range-extender vehicles) has dropped off the network. Engine power is reduced or limp-home mode is forced.
Affected components
- Powertrain control module
- Can bus wiring
Common causes
- High likelihood: PCM B unpowered
- Low likelihood: Gateway module routing CAN messages incorrectly
- Low likelihood: CAN terminating resistor (120 Ω) drifted out of spec
Possible symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Diagnostic notes
- The malfunction indicator lamp may illuminate
- Reduced-power or limp mode may occur
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.