U0442
Invalid Data Received From ECM/PCM B
A receiving module detected implausible data from the second engine/powertrain control module (ECM/PCM B — used on V-engines with one ECU per bank or master/slave architectures). Engine torque, RPM or load values fail plausibility checks and are rejected.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
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
Common causes
Ordered by how often each turns out to be the cause.
- Module internal fault or sensor input driftCommon
- Software version mismatch after replacementPossible
- Gateway module routing CAN messages incorrectlyLess likely
Parts involved
- ECM PCM B
U0442 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.