U0157 indicates that the Powertrain Control Module (PCM) has lost communication with the Information Center B (often the instrument cluster or body control module). This communication failure prevents the PCM from receiving or sending data needed for proper vehicle operation.
Corroded pins, broken wires, or loose connectors are the most common source of lost communication.
A short to ground or an open circuit on the network can interrupt data flow between modules.
Internal failure of the instrument cluster or body control module can stop it from responding to PCM requests.
A malfunction within the PCM’s communication transceiver can prevent it from transmitting signals, though this is less common than wiring issues.
Rarely, a corrupted firmware version may cause intermittent communication loss; re‑flashing the module can resolve it.
In most cases the PCM is not the culprit; wiring, connectors, or the Information Center B are far more likely causes. Replacing the PCM without confirming a fault is usually unnecessary.
After repairing the underlying issue, clear the codes with a scan tool and drive the vehicle through a readiness cycle. If the repair was successful, the code should not return.
A severely low battery voltage can cause communication dropouts, but it typically triggers other battery‑related codes first. Verify battery voltage is within specification before assuming it’s the root cause.
Driving is generally possible, but you may lose critical gauge information or experience reduced performance. It’s advisable to diagnose and repair the issue promptly.