What does it mean?
The module compares the pulse train from camshaft position sensor "B" on bank 2 with the crankshaft reference on every revolution, and it expects a fixed number of clean edges in a repeatable position. This code is stored when that pulse train briefly disappears, gains extra edges or jumps out of position and then returns to normal, so the signal is electrically present but not trustworthy.
Unlike a permanent circuit fault, the condition comes and goes, which usually points to a mechanical or connection problem that only shows up under vibration, heat or a particular load. Every dropout costs the module its camshaft reference for that bank, so injection and valve timing control are momentarily disturbed. The fault often stores after several separate events rather than on a single occurrence, and the MIL (check engine lamp) may only come on after the pattern repeats.
Symptoms
- MIL (check engine lamp) on, sometimes only after the fault has occurred on several trips
- Brief stumble or a momentary cut in power that clears by itself
- Occasional rough idle or a single shudder felt while cruising
- Longer than usual cranking on some starts and normal starting on others
- Random hesitation on acceleration without a clear pattern
- Occasional stall at idle or when coming to a stop, often followed by a normal restart
Likely causes
- Loose, partially seated or corroded connector at the sensor, which breaks contact under engine vibration
- Chafed or brittle signal wire that touches ground or opens intermittently as the engine rocks on its mounts
- Metal debris collected on the sensor tip, distorting the magnetic field and adding false edges
- Damaged, cracked or loose target ring on the exhaust camshaft, or a tooth deformed by earlier repair work
- Camshaft end float or worn bearing journals allowing the air gap to change while running
- Stretched timing chain, worn guide or a tensioner losing pressure at low engine speed and hot idle
- Poorly routed secondary ignition leads or an unshielded accessory injecting interference into the signal wire
How to fix it
- Read the freeze frame and note whether the events cluster around a specific temperature, engine speed or road surface
- Inspect the connector for loose terminals, a damaged lock, oil contamination and a hardened seal, then check the harness for rubbing along the cam cover and the timing case
- Record the camshaft signal on a scope or with a graphing meter while the engine idles and is wiggle tested at the sensor, the harness and the module connector
- Take a live data recording during a drive that reproduces the recorded conditions and look for pulse loss synchronised with bumps or torque changes
- Remove the sensor and check its tip for metal debris and its mounting for looseness, and inspect the target ring for chipped or bent teeth
- Check camshaft end float and timing chain condition if the signal wanders in position rather than dropping out completely
- Repair or replace the item proven faulty, clear the memory and confirm over several heat cycles and a mixed road test that no further dropouts are logged