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Jeep WJ 4.7L V8 P0340 and P1391 Fault: Cam & Crank Sensor Issues After Replacement

Model: Jeep WJ Fault Code: P0340 Posted: 2016-04-10 03:01

Hi, I'm experiencing persistent fault codes P0340 and P1391 on my Jeep WJ with a 4.7L V8 engine. The vehicle pulls these codes under load—especially during towing or climbing steep hills—and has shown symptoms including misfires, engine stalling in reverse, and sudden loss of power. Both the crankshaft and camshaft position sensors have already been replaced, yet the issue persists. Jeep dealerships are unable to identify a root cause. I was originally planning to install a lift kit, but I've put that on hold until a reliable fix is found. Any insights or troubleshooting steps would be greatly appreciated. Thank you, Rosecevans

Related fault codes

P0340P1391

Comments (2)

Anonymous 2016-04-10 09:50

Check the circuit to the Bank 1 Intake Cam Position Sensor as well as the Crankshaft Position Sensor. P1391 indicates an intermittent loss of signal from either the CMP (Cam Position) or CKP (Crank Position) sensors.

Anonymous 2016-04-10 10:35

The codes are P0340 and P1391; the vehicle is stock with no aftermarket parts installed. I suspect a camshaft position sensor (CMP) issue. Possible causes include incorrect cam timing—such as a worn chain, faulty tensioner, or damage to the target wheel (tone ring/pulse ring). A loss of signal can be verified using an oscilloscope. I believe these are original Jeep components; aftermarket sensors may introduce reliability issues. Dealerships often recommend OEM parts first.