What it means
The CMP signal voltage is above the upper threshold. Either excessive sensor output or a short to supply voltage.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Camshaft Position Sensor A on bank 1, or the single cam sensor on a one-bank engine, reports cam position to the engine control module. This code means the input voltage is above the module's upper limit, often because the signal wire is shorted to a supply or the sensor has failed.
Common causes
Most likely first.
- Signal wire shorted to supply voltage
- Sensor failed
- Connector pins corroded - high contact resistance
Symptoms
- Check engine light on
- Power loss especially in mid-rpm range
- Possible rough idle or stalling
- Increased fuel consumption
How to diagnose it
- Save freeze-frame data and monitor Sensor A data for bank 1 to confirm the high input and whether it stays high during cranking and running.
- Inspect the Sensor A connector and bank 1 harness for corrosion, damaged pins, chafing, or contact with a supply wire.
- Test the signal circuit for a short to supply voltage and check connector pin contact and wiring continuity to the manufacturer's specification.
- Test Sensor A using the manufacturer's procedure if the wiring and connector pass inspection.
- Check for related crankshaft or camshaft timing codes to determine whether the high input is accompanied by a signal or timing problem.
Common fixes
- Repair a damaged Sensor A connector or restore a loose pin.
- Repair the signal wire if it is shorted to a supply.
- Replace Sensor A on bank 1 if it fails the manufacturer's tests.
- Repair any associated wiring damage found during circuit testing.
Can I keep driving?
Limit driving until the high signal is diagnosed; the engine may lose power, run roughly, or stall if the module cannot use Sensor A's position information. Stop if it stalls repeatedly or loses substantial power.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.