What Does P0342 Mean?
The camshaft position sensor A on bank 1 is reporting a low input signal to the ECM. The voltage on the CMP sensor circuit is below the expected minimum operating threshold. The engine may fail to start, start but run rough, or default to a degraded batch-fire fuel injection mode with reduced performance and efficiency.
Safety Warning
If the engine runs, it may be in degraded mode with reduced performance. Do not drive if the engine stalls or refuses to start. A sudden loss of CMP signal while driving can cause the engine to stumble or stall. Limit driving to reaching a repair facility.
Common Causes
35%
Failed CMP sensor with weak or non-functional internal sensing element
25%
Open or high-resistance connection in the CMP sensor signal circuit preventing signal from reaching the ECM
15%
Missing or low 5V reference voltage to the CMP sensor due to wiring fault or shared reference circuit overload
15%
Short to ground on the CMP sensor signal wire pulling voltage below threshold
10%
Oil-soaked CMP sensor connector causing signal degradation (common when valve cover gaskets leak)
Diagnostic Steps
1
With key on engine off, measure voltage at the CMP sensor connector — verify the 5V reference and ground circuit are present; missing reference voltage means the sensor cannot generate a signal regardless of sensor condition.
2
Disconnect the CMP sensor and measure the signal wire voltage at the ECM connector while the key is on — this verifies the signal wire is not shorted to ground between the connector and ECM.
3
Inspect the CMP sensor connector for oil contamination — oil leaking past the valve cover gasket commonly wicks down the wiring and fills the connector, causing low-signal conditions. Clean thoroughly.
4
Check the 5V reference circuit for loading from other sensors on the shared reference — a shorted sensor elsewhere on the same 5V reference line can pull the voltage low for all connected sensors.
5
If power, ground, and wiring are confirmed good, replace the CMP sensor — measure the output signal of the new sensor while cranking to verify it produces a clean, full-amplitude switching signal.
Estimated Repair Cost
$80 - $500
Parts + labor, varies by vehicle and location
The camshaft position sensor A on bank 1 is reporting a low input signal to the ECM. The voltage on the CMP sensor circuit is below the expected minimum operating threshold. The engine may fail to start, start but run rough, or default to a degraded batch-fire fuel injection mode with reduced perfor...
The most common cause of P0342 (Camshaft Position Sensor A Circuit Low Input (Bank 1)) is: Failed CMP sensor with weak or non-functional internal sensing element
Typical repair costs for P0342 range from $80 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
If the engine runs, it may be in degraded mode with reduced performance. Do not drive if the engine stalls or refuses to start. A sudden loss of CMP signal while driving can cause the engine to stumble or stall. Limit driving to reaching a repair facility.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0342 to identify the root cause.
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Quick Info
Category
Powertrain
System
Ignition System
Difficulty
Type
Generic (SAE)
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