P1218 GMC Possible Causes
- The Powertrain Control Module (PCM) currently has no resistance value
- The Powertrain Control Module (PCM) cannot read the resistance value
How to Fix GMC P1218 Code?
Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.
Technical Notes
The P1218 code is typically set when the resistance is missing from the PMD or when the system has been disrupted and the ECU is relearning the resistance value. Most of the time, the issue is the missing resistance. Repeatedly cycling the key will relearn the resistance value.
Possible Symptoms
- Engine light on (or engine service warning light soon)
P1218 GMC Meaning
The Powertrain Control Module (PCM) uses a calibrated resistance inside the injection pump to determine fuel rates. The resistance value is stored in the PCM’s memory. If the PCM’s memory has been disrupted or replaced, the PCM will relearn the resistance value on the next ignition cycle. The code is set when the key is turned on or the engine is running and the PCM does not detect a correct current valid resistance value, or it has determined that it was unable to read the current resistance value.