The P1374 code on your 2022 Chevrolet Suburban indicates a communication problem between the PCM and the ignition control module or crankshaft position variation learning system. This GM-specific code affects your Suburban's 5.3L or 6.2L V8 engine's ability to optimize ignition timing and detect misfires accurately.
Understanding P1374 on Suburban
The crankshaft position variation learning system uses precise measurements from the crankshaft position sensor to detect misfires and optimize ignition timing. Code P1374 sets when the PCM loses communication with this system or receives invalid data from the ignition diagnostic processor. This can affect misfire detection accuracy and overall engine performance.
Common Symptoms
- Check engine light on
- Rough idle or engine vibration
- Hesitation during acceleration
- Multiple cylinder misfire codes may accompany P1374
- Engine may run normally despite code
- Failed emissions inspection
Primary Causes
- Faulty crankshaft position sensor
- Damaged reluctor ring on crankshaft
- Wiring issues between CKP sensor and PCM
- PCM internal communication fault
- Excessive crankshaft endplay affecting sensor readings
- Crankshaft position variation not learned after battery disconnect
Diagnostic Procedure for 2022 Suburban
Begin by attempting to perform a crankshaft position variation relearn procedure using a GM-compatible scan tool. If the relearn fails repeatedly, inspect the crankshaft position sensor and its wiring. Check for proper sensor air gap and reluctor ring condition if accessible. Monitor CKP sensor signal quality during cranking and running. Test wiring continuity between the sensor and PCM. Check for any TSBs related to P1374 on 2022 Suburbans.
Repair Solutions
If the relearn procedure completes successfully, clear codes and test drive. Replace the crankshaft position sensor if signal quality is poor or erratic. Repair any damaged wiring found during inspection. If the reluctor ring is damaged, more extensive repair may be needed. In rare cases, PCM replacement or reprogramming may be required if internal communication faults are confirmed.