| DTC Data Sheet | |
| System | Powertrain |
| Standard | SAE J2012 / ISO 15031-6 |
| Fault type | Circuit High |
| Official meaning | Camshaft Position Sensor "A" Circuit High Input (Bank 1) |
The bank 1 CMP signal voltage is above the maximum threshold — typically a short to power, open ground, or failed sensor.
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P0343 Quick Answer
The bank 1 CMP signal voltage is above the maximum threshold — typically a short to power, open ground, or failed sensor.
What Does P0343 Mean?
Camshaft Position Sensor "A" Circuit High Input (Bank 1). The bank 1 CMP signal voltage is above the maximum threshold — typically a short to power, open ground, or failed sensor.
Symptoms
- No-start or extended cranking
- Stalling
- Misfires
- Check engine light
Common Causes
- Short to 12 V on the CMP signal wire
- Open ground in the CMP circuit
- Failed CMP sensor (output stuck high)
- Damaged PCM driver or signal-conditioning input (rare)
Diagnosis Steps
You’ll need a scan tool capable of reading live powertrain data, a digital multimeter, and access to the wiring diagram for the specific platform.
- Verify CMP ground integrity at the connector with engine running.
- Disconnect CMP and check whether signal returns to plausible values (rules out PCM input damage).
- Inspect for harness damage where the signal wire passes near 12 V circuits.
Possible Fixes
- Replace CMP
- Repair shorted-to-power wiring
- Ground circuit repair
Can I Still Drive With P0343?
The vehicle will usually still drive with P0343 stored, but performance, drivability, or emissions will be degraded. The PCM may inhibit emissions monitors and limit closed-loop fueling adjustments. Drive to a workshop, but don’t ignore the code long-term.
How Serious Is This Code?
P0343 is a moderate-priority fault. It will not prevent the engine from running, but unaddressed it can cascade into related faults or damage downstream components such as the catalytic converter. Address within a few drive cycles.
FAQ
Will P0343 clear itself?
Only if the underlying fault was intermittent and self-corrected. Most root causes are persistent and require physical repair.
Can I clear P0343 without fixing it?
You can clear it with a scan tool, but it will return as soon as the fault condition reappears — typically within one or two drive cycles.
Is P0343 related to other codes?
Often, yes. Adjacent codes in the same circuit or system frequently set together — if P0343 is present, scan for related codes and address them as a group.