TECH TIP: Lack of Maintenance Causes Jeep No Start – Numerous DTCs
TECH TIP (courtesy from ALLDATA)
Vehicle: 2011 Jeep Compass, 2WD, L4-2.4L, Automatic transmission/transaxle
Problem: The Jeep was in the shop because of an intermittent starting problem and the malfunction indicator light (MIL) was on.
Case Details: The technician connected a scanner and pulled the following diagnostic trouble codes (DTCs).
- P0016 – Crankshaft Position to Camshaft Position Correlation (Bank 1 Sensor A)
- P0339 – Crankshaft Position Sensor A Circuit Intermittent
- P0335 – Crankshaft Position Sensor A Circuit
- P0522 – Engine Oil Pressure Sensor/Switch Circuit Low Voltage
First, the technician checked the engine oil level and found it to be two quarts low, so he changed the oil and filter. Next, he replaced the CKP sensor and performed a crank relearn with his scan tool. After that, DTC P0016 was the only code that came back. He noted that the intake cam solenoid was working properly.
At this point, he called ALLDATA Tech-Assist for some friendly advice. The Tech-Assist consultant recommended the following tests.
- Reconnect the scan tool and compare the actual vs desired camshaft position in degrees with the engine running.
- Check the engine oil pressure (should be a minimum of 14 psi at hot idle).
- With the engine off, pull the valve cover to check valve timing (make sure the camshaft actuator (pulley) is locked in place).
- Inspect the timing chain and tensioner while the valve cover was off.
The technician found that the actual vs desired camshaft position always matched with the engine running and the P0016 DTC came back as soon as the engine started. The oil pressure was at specifications. He removed the valve cover, and with the actuator locked, he could see that the chain was stretched, and the tensioner piston was fully extended. There was no doubt that the lack of maintenance was the root cause of all the problems.
Confirmed Repair: The technician replaced the timing components, cleared the DTCs, started the engine in the shop a few times then road-tested the vehicle. There were no further issues. Fixed!