P034BCrankshaft Position Sensor - Crankshaft Direction Incorrect
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- Direction-sensing (bidirectional) crank sensors count the rest position for start-stop even when the crankshaft rocks back after shut-off. In normal running the sensor must never report reverse rotation – if it does, the signal is disturbed. GM sets P034B after at least 3 direction reversals within 10 s at 400 to 2,000 rpm and an airflow of at least 1.5 g/s, after two trips; the diesel uses the same thresholds. GM bulletin 17-NA-317 describes the 3.6 V6 (LFY) in the 2018 Buick Enclave and Chevrolet Traverse: interference in the sensor circuit caused P034B with P0506, low idle or stalling after an autostart, transmission slip above 65 km/h and cruise control dropping out; the remedy was a revised sensor wiring. Result: start-stop disabled, possibly reduced power.
- What you may notice
- Check engine light on
- Low idle or stalling after an autostart
- Start-stop off, possibly reduced power
- Follow-on effects such as transmission slip or cruise control dropping out (GM LFY)
- Likely causes
- LikelyInterference in the sensor circuit (wiring routed next to switching lines)
- PossibleDirection-sensing crankshaft position sensor faulty
- PossibleGround or connector fault
- RareTone wheel or air gap
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.