P0340 and more

[MATTBRUNSON9]

Alright i have a 1999 4.0 3spd auto originally with a 6spd manual swap in it. throwing P0204,P0206,P0201,P0205,P0203,P0202,P0340, and P1391.

P0201-06 are injectors 1-6 circuit open/malfunction

The dreaded P0340 is the camshaft position sensor

P1391 is CMP/CKP signal intermittent.

What I've done: New CMP (twice), New CKP, New plugs, and new plug wires

Any ideas on where to go next?

 

[Chris]

Alright i have a 1999 4.0 3spd auto originally with a 6spd manual swap in it. throwing P0204,P0206,P0201,P0205,P0203,P0202,P0340, and P1391.

P0201-06 are injectors 1-6 circuit open/malfunction

The dreaded P0340 is the camshaft position sensor

P1391 is CMP/CKP signal intermittent.

What I've done: New CMP (twice), New CKP, New plugs, and new plug wires

Any ideas on where to go next?

Since you’ve already replaced the camshaft position sensor (CMP), crankshaft position sensor (CKP), plugs, and wires, it might be time to dig a little deeper. Here are some things to consider:

1. Wiring and Connectors: Check all the wiring related to the injectors and the sensors. Look for frayed wires, loose connections, or corrosion that might cause intermittent signals. Pay close attention to the connectors for the CMP and CKP, as well as the injector connectors.
2. Grounds: Make sure all your ground connections, especially for the engine and the ECM (engine control module), are secure and free of corrosion. A poor ground can cause erratic sensor readings.
3. ECM Issues: It's possible that your ECM has developed a fault, especially since you are getting multiple injector codes and the camshaft position error. Check if the ECM is getting proper voltage and ground, and consider re-flashing it if there's a chance it's corrupt. If necessary, @Wranglerfix can test your ECM for you. He's wonderful to deal with.
4. Sensor Timing: Given that you have a 6-speed manual swap, ensure that the timing of the sensors is correct and aligned properly. If the timing was off during the swap, it could cause the P0340 and P1391 codes.
5. Electrical Testing: Use a multimeter to check the signal voltage at the sensors and injectors. If you’re not getting the expected voltage, you might have a short circuit or an open circuit somewhere.
6. Refer to the Wiring Diagrams: Look up the specific wiring diagrams for your model to trace back the injector circuits and sensor signals to find any possible shorts or open wires. Jeep Wrangler TJ wiring diagrams can be found in the back of the FSMs which are free to download here.
7. Additional Diagnostic Approach: If you have access to a scanner with live data capabilities, check the readings from the CMP and CKP when the engine is running to see if they are behaving as expected. This can help to further isolate the issue.
8. Check for Vacuum Leaks: While not directly related to your codes, a vacuum leak can cause various performance issues that might lead to errors in sensor readings.