P1258 GMC Possible Causes
- Faulty engine coolant temperature
- Engine coolant temperature circuit open or shorted
- Poor electrical connection in the engine coolant temperature circuit
How is GMC P1258 Code Repair Performed?
Start by checking the “Possible Causes” listed above. Visually inspect the wiring harness and related connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
- Engine light on (or service engine soon warning light)
P1258 GMC Meaning
To reduce engine temperature, the Powertrain Control Module (PCM) has the ability to disable a number of fuel injectors during engine overheating. The PCM considers engine overheating whenever the Engine Coolant Temperature (ECT) reaches a predetermined temperature. This DTC is set to show that the PCM has detected an overheating condition and the system has engaged protection mode.