Fix P0342: Mechanic’s solutions that WORKED

The P0342: Camshaft Position Sensor Circuit Low code indicates that the camshaft position sensor circuit is sending a signal that is lower than expected. This sensor plays a crucial role in monitoring the position of the camshaft and helping control fuel injection and ignition timing. A fault in this circuit can lead to various engine performance issues.

P0342 quick overview

Meaning	P0342: Camshaft Position Sensor Circuit Low
Is it serious?	This code can be serious as it may lead to drivability issues, poor engine performance, or even prevent the engine from starting.
Possible causes	– Faulty camshaft position sensor – Damaged or corroded sensor wiring and connectors – Misalignment of camshaft position sensor – Problems with the sensor’s power supply circuit – Issues with the PCM (Powertrain Control Module)
How to diagnose?	Inspect Sensor and Wiring: Check the camshaft position sensor and its wiring for any visible damage or disconnections. Check Sensor Alignment: Ensure the camshaft position sensor is properly aligned and mounted. Test Sensor Output: Use diagnostic tools to test the sensor’s output and compare it against manufacturer specifications. Examine Power Supply: Check the power supply circuit to the sensor for any issues. Consider PCM Issues: Evaluate the PCM for any potential faults related to the camshaft position sensor circuit.

How to fix P0342 – learn from mechanics

I looked into P0342 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Porsche

Vehicle Information: 2002 Porsche Boxster Roadster S 3.2L

Issue + Repair History: MIL lamp on. Seeking the location of the camshaft position sensor.

Computer Codes & Descriptions: P0342 – Cam Position Sensor

Suggestions to Fix Issue:

• Locate cam sensors on the rear of each cylinder head on the intake cams.
• Check the intermediate shaft bearings, as they can cause similar codes.
• Warn customer about potential failing shaft bearing, especially if car has over 50,000 miles.
• Contact a specialist for details on repairing the shaft bearing issue.

Final Fix: Found the sensor on the left front of the engine, behind the driver’s seat.

Case #2: Kia

Vehicle Information: 2005 Kia Sorento EX 3.5L

Issue + Repair History:

• Intermittent crank, no start condition.
• Code P0342 set, but not currently a problem.
• Unknown if the timing belt has been replaced.
• This is the vehicle’s first visit.

Computer Codes & Descriptions:

• P0342 – Cam Sensor A Circuit Low Input B1

Suggestions to Fix Issue:

• Replace the cam sensor, especially if the timing belt has not been done.
• Consider replacing the crank sensor along with the cam sensor and timing belt.
• If having starting issues, unplug the cam sensor and try to start the vehicle.
• Check resistance to the sensor and ensure timing marks are correctly aligned.
• Note that the cam sensor sequences fuel injection and may not prevent starting but can cause extended cranking or driveability issues.

Final Fix:

• Disconnected the cam sensor, which caused the engine to kick back as if the firing order was off, but it did not run.
• Replaced the cam sensor and cleared the code.
• The vehicle runs properly after the repair, with no further issues reported.

Case #3: Pontiac

Vehicle Information: 1996 Pontiac Sunfire SE 2.2L

Issue + Repair History:

• Cooling fan staying on and MIL lamp on.
• Scanned and found system code P0342 (Camshaft Position Sensor).
• Followed test and inspection procedures; replaced CMP sensor.
• Tested all circuits between CMP sensor and PCM.
• Replaced PCM with a used one, but the issue persisted.

Computer Codes & Descriptions:

• P0342 – Camshaft Position Sensor

Suggestions to Fix Issue:

• Reprogram the PCM.
• Check and clean the computer ground connection at the bellhousing.
• Investigate potential shorted wire in the fan relay system between the relay and the thermal fan sensor/switch.

Final Fix:

• Found rust between the CMP sensor and the engine, which distanced the sensor from the gear causing a bad reading.
• Cleaned the rust away, resolving the problem.

Case #4: Ford

Vehicle Information: 1994 Ford Mustang 3.8L

Issue + Repair History:

• Lack of acceleration, hesitation in all conditions, and backfiring when accelerating suddenly.
• Codes P0171, P0174, P0342 present.
• Found the cause of lean mixture (P0171 and P0174) due to incorrectly seated PCV valve.
• Cam sensor producing only around 22 Hz; hard fault on cam sensor code P0342.

Computer Codes & Descriptions:

• P0171 – Lean Mixture Bank 1
• P0174 – Lean Mixture Bank 2
• P0342 – Camshaft Position Circuit Low

Other Test Results:

• 35 psi at idle, 34 psi at 2000 rpm.
• Spark advance of 24 at idle.
• MAF (Mass Air Flow) sensor okay.

Suggestions to Fix Issue:

• Check for a vacuum leak or unmetered air causing both banks to run lean.
• Inspect exhaust back pressure.
• Evaluate the DPFE sensor, as it is known for causing the cam code due to shared reference voltage.
• Use a two-channel lab scope to compare the cam and crank sensor waveforms for synchronization.

Final Fix:

• Replaced the cam sensor and reset the KAM (Keep Alive Memory).
• The code was cleared, and the vehicle ran fine after the repair.

Case #5: Chevrolet

Vehicle Information: 1998 Chevrolet Cavalier 2.2L

Issue + Repair History:

• MIL lamp on with codes P0335 and P0342.
• Customer reported intermittent coughing during startup.
• Unable to replicate the issue during testing.
• Found no wiring or connection problems.
• Replaced cam and crank sensors.
• Car returned with only P0335 code present.
• Suspected issues with timing chain, starter, or ECM.

Computer Codes & Descriptions:

• P0335 – CKP Sensor
• P0342 – CMP Sensor

Suggestions to Fix Issue:

• Ensure sensors are original equipment.
• Labscope pattern check at PCM; replace PCM if pattern is poor.
• Check plug wire connections at coil towers for corrosion or high resistance.
• Investigate potential timing chain problems to prevent possible valve damage.
• Consider the possibility of timing being off a tooth or two.
• Inspect coil towers for corrosion.

Final Fix:

• Found a bad starter intermittently glitching during cranking, causing a false crank sensor code.

Advice	Brief Description of Diagnostic Step
Check Cam Sensor Connections	Inspect the camshaft position sensor’s wiring and connectors for damage or poor connections.
Replace Cam Sensor	If diagnostics indicate, replace the camshaft position sensor with a new one.
Inspect Wiring Integrity	Examine the wiring harness for any signs of damage, corrosion, or improper connections.
Test Cam Sensor Output	Use a scope to test the cam sensor’s output and compare it with standard specifications.
Clean and Check Sensor Mounting Area	Ensure the area where the sensor is mounted is clean and free from obstructions or rust.
Reset/Reprogram PCM if Necessary	After replacing the sensor, reset or reprogram the Powertrain Control Module (PCM) as needed.
Check for Related Issues	Look for related issues like timing chain problems or issues with other sensors that might affect the cam sensor’s performance.