P0340 & P0344

[sgesbeck]

Got code P0344 camshaft position sensor intermittent about two weeks ago on my 2006 Wrangler Sport 4.0 Automatic. The engine would buck at about 2500 rpm during acceleration after a stop. This jeep was mine originally and then my youngest son drove it for about 9 years. When I retired I gave him and his wife my 2018 Wrangler JK Sahara and took back the 2006 TJ for a restoration project. Anyway, probably 7 or 8 years ago we replaced the Oil Pump Drive Assembly. We had bought a new Cam Shaft Position sensor before we realized the opda came with the sensor. Since I never throw things away I installed the new sensor and cleared the code. The next time I drove it the bucking started again and this time the code was P0340 Camshaft Position Sensor. Since it was a new sensor I suspected a wiring issue.
I checked the wiring on the Camshaft Position Sensor along the engine and behind the dipstick and everything was good. I next checked the wiring for the Crankshaft Position Sensor and sure enough there were exposed wires. Unfortunately this is on the wiring going back to the pcm. I ordered a new sensor and short wire harness. I reinstalled the Camshaft Position Sensor (since it wasn't the root cause), removed, cleaned and reinstalled the Crankshaft Position Sensor, and then spliced in the new wire harness with solder & seal wire connectors. Since I had the negative cable disconnected from the battery I cleaned the connections at the firewall and the engine more for preventive maintenance than anything else.
When I started it there was no check engine light because of disconnecting the battery. I let it idle in the driveway while I checked air pressure in all three vehicles (killing time). Took the jeep for about a 15 mile drive with several stops and starts and no issues. I've had this Jeep long enough to know that problems often reoccur but this seemed like an obvious smoking gun. I'll update if the code(s) return.

 

[Chris]

Got code P0344 camshaft position sensor intermittent about two weeks ago on my 2006 Wrangler Sport 4.0 Automatic. The engine would buck at about 2500 rpm during acceleration after a stop. This jeep was mine originally and then my youngest son drove it for about 9 years. When I retired I gave him and his wife my 2018 Wrangler JK Sahara and took back the 2006 TJ for a restoration project. Anyway, probably 7 or 8 years ago we replaced the Oil Pump Drive Assembly. We had bought a new Cam Shaft Position sensor before we realized the opda came with the sensor. Since I never throw things away I installed the new sensor and cleared the code. The next time I drove it the bucking started again and this time the code was P0340 Camshaft Position Sensor. Since it was a new sensor I suspected a wiring issue.
I checked the wiring on the Camshaft Position Sensor along the engine and behind the dipstick and everything was good. I next checked the wiring for the Crankshaft Position Sensor and sure enough there were exposed wires. Unfortunately this is on the wiring going back to the pcm. I ordered a new sensor and short wire harness. I reinstalled the Camshaft Position Sensor (since it wasn't the root cause), removed, cleaned and reinstalled the Crankshaft Position Sensor, and then spliced in the new wire harness with solder & seal wire connectors. Since I had the negative cable disconnected from the battery I cleaned the connections at the firewall and the engine more for preventive maintenance than anything else.
When I started it there was no check engine light because of disconnecting the battery. I let it idle in the driveway while I checked air pressure in all three vehicles (killing time). Took the jeep for about a 15 mile drive with several stops and starts and no issues. I've had this Jeep long enough to know that problems often reoccur but this seemed like an obvious smoking gun. I'll update if the code(s) return.

View attachment 584825

Those wiring issues can indeed lead to all sorts of erratic behavior, especially with camshaft and crankshaft position sensors.

Hopefully, the repairs will hold up, and the bucking and codes will be a thing of the past. Keep us updated on how things go with the Jeep; we love to hear success stories, especially from restoration projects. Best of luck with your ongoing work on the TJ!

 

[macleanflood]

Might need to resync or check the OPDA's phasing with a scan tool.

I'd be checking more of that harness and now's a great time to check and clean all your grounds and battery terminals.

-Mac

P.S. Is it the original PCM?

 

[sgesbeck]

Might need to resync or check the OPDA's phasing with a scan tool.

I'd be checking more of that harness and now's a great time to check and clean all your grounds and battery terminals.

-Mac

P.S. Is it the original PCM?

Not a bad idea to check phasing. Not sure I can do it with the blue driver scan tool though. I did clean the ground connections and battery terminals. Also unclipped connections and cleaned with electronics spray cleaner. inspected all the wires on top during the restoration and used new wire loom. Found exposed wires on one of the O2 sensors and a leak on the back of the valve cover. We had thought the oil was from the rear main seal which we did twice. There is a grounding strap back there that was saturated in oil.

 

[sgesbeck]

Update 1/22/2025: The next day after replacing the wire harness on the Crankshaft Position Sensor the CEL came back for code P0344 camshaft position sensor intermittent. I decided to replace the original Crankshaft Position Sensor with the new one that came with the wire harness. I cleared the code and drove about 8 miles when the CEL came on but this time for P0340 camshaft position sensor. I reinstalled the original Crankshaft Position Sensor, cleared the code, went for a test drive and the CEL came back with P0344 camshaft position sensor intermittent. After reading through some other posts here I bought the Echlin Ignition Camshaft Position Sensor Part #: ECH CSS1159 from the local NAPA Auto Parts. I have since driven the Jeep about 280 miles without the CEL returning. I'm South of Tucson, Arizona and we've had several morning below freezing which some posts suggested contributes to the issue.

Thankful for the resources available here to help troubleshoot issues. Maybe this will help someone else with similar issues.

 

[sgesbeck]

The saga continues. I starting to thing the Check Engine Light just tells me the Jeep is running LOL! Anyway, on 2/2/2025 the CEL came back on but this time for P0016 Crankshaft Position – Camshaft Position Correlation Bank 1 Sensor A. My son and I replaced the Dorman Oil Pump Drive Assembly that we installed back in November 2019 with a new Crown OPDA. The old Dorman OPDA had vertical play in the shaft but the gears didn't show any excessive wear. The good news was the camshaft itself didn't show much wear. After the install, we cleared the codes and took the Jeep for a test drive with no issues. That finally resolved that issue.

However, three days later (2/5/2025) while driving to a hike on a moderately steep road in 80 degree weather, the Jeep seemed to sputter a few times. No CEL light but when I got to the destination I put the checked for codes and there was a pending code P0303 Cylinder 3 Misfire Detected. I let the Jeep sit for about 4 hours while I hiked and on the way home, going downhill, it seemed to be fine.

I checked this forum and decided to replace the original heat shield over the exhaust manifold since it was in terrible shape, install the insulation from the TSB over injector #3, and replace the spark plugs with Autolite XP985 Iridium plugs. I installed everything on 2/14/2025 and using feeler gauge set the plug gap to 0.040". I reset the codes and everything seemed good. No misfires, no sputtering.

On 3/3/2025, after filling gas tank which was near empty, the CEL came on. I pulled over and did the quick ignition key check and saw I had code P0303 again. I was driving to the same hiking spot up the moderately steep road and it ran fine. No obvious misfires or sputtering. I reset the code when I got to the parking lot, did about a six hour hike, and drove home without any issues. It is about a 24 mile drive.

No CEL again until Monday 3/17/2025. I had four new tires installed at a local shop. I did the quick check and it was P0303 again. I drove home with the CEL on and again there were no observable issues. I cleared the code when I got home.

Yesterday, I drove to a different hiking spot and the CEL came on almost immediately for P0303. This spot I drove to also has moderate elevation gain and about 4 miles of dirt road through a few dry washes. The Jeep again showed no signs of misfire. I even tried to really push the RPMs on a few hills and it the engine seemed great. In fact, with the new tires, it felt like driving a new Jeep (almost LOL).

I'm stumped at this point. Any suggestions would be greatly appreciated. I believe my son replaced the ignition coil back in 2019 but I don't know the brand.

 

[JKP]

Check the MAP sensor.

With the key on, engine off, check the MAP sensor reading.

With your cell phone, download a barometer app, take the station pressure reading and compare. They should be virtually the same. You can't use the weather report reading as it is normalized to sea level.

The PCM only updates it's elevation reading on startup or WOT. The rest of the time it just measures the manifold pressure and uses the last elevation reading for the air density.

 

[sgesbeck]

Check the MAP sensor.

With the key on, engine off, check the MAP sensor reading.

With your cell phone, download a barometer app, take the station pressure reading and compare. They should be virtually the same. You can't use the weather report reading as it is normalized to sea level.

The PCM only updates it's elevation reading on startup or WOT. The rest of the time it just measures the manifold pressure and uses the last elevation reading for the air density.

I'll do that today and let you know what I find. When we replaced the plugs and installed the heat shield we disconnected the MAP and moved the intake out of the way which could have damaged the connector.

Thanks for the help!

 

[sgesbeck]

Downloaded the Barometric Pressure App. Reading is 30.34 inHg. The MAP sensor with the engine off reads 27.5 inHg so a difference of -2.84 inHg or -9.4% off. Is that enough difference to warrant changing out the MAP sensor and the connector wire? The connector wire seems to have melted plastic where it goes into the wiring rail. I guessing the melted plastic is from the damaged/missing exhaust manifold heat shield.

When I started the engine, MAP dropped to 11.2 inHg which I assume means there is vacuum. Not sure if that is relevant.

Thanks for any feedback.

 

[JKP]

The 30.34 sounds like the meteorological pressure, look to see if the app has a setting for station, or absolute.

Yes, the difference between 27.5 and 11.2 is vacuum. 16.3 in hg.

 

[sgesbeck]

The 30.34 sounds like the meteorological pressure, look to see if the app has a setting for station, or absolute.

Yes, the difference between 27.5 and 11.2 is vacuum. 16.3 in hg.

I set the units on the App to the same as the units from the Manifold Absolute Pressure (MAP) sensor which is inches of mercury (in Hg). When I switched the App to psi it returns 14.90 psi which is absolute pressure and so the App is returning the meteorological station pressure in absolute pressure regardless of which units I select.

Since the two pressures are off by 2.84 inHg can I assume the sensor is bad?

 

[JKP]

It's not the units setting.

 

[sgesbeck]

It's not the units setting. View attachment 602275

Got it. My phone (Samsung S21) doesn't have a barometric pressure sensor. The pressure "is taken via the internet from the nearest meteorological station" so you're right it is probably the normalized pressure. My son and his wife will be over for dinner later and I think she has an iPhone which might have the barometric pressure sensor. I checked and we replaced the MAP sensor in 11/2022 with a Standard Ignition part # AS345.

I'll post an update later. Again, I really appreciate the help!

Gracias!

 

[JKP]

Oh, yeah, if your phone doesn't have the sensor, you're getting the normalized.

My MAP was off enough that it was causing it run lean.

 

[sgesbeck]

Last night I checked the Manifold Absolute Pressure (MAP) sensor against local station barometric pressure uses my daughter-in-law's iPhone. MAP measured 27.5 inHg and the iPhone measured 27.45 inHg. It doesn't seem like a significant difference, especially considering rounding (0.18% seems like reasonable tolerance). While collecting live data with the engine off I wiggled the wires and gently pulled on the connector and it didn't change the reading.

Not really thinking it is the MAP. Other ideas? Again, it runs great with no discernable misfire....just P0303 keeps coming back.

 

[JKP]

The MAP should be good.

Measure the resistance of the injectors and see if number 3 is different or if it is different when hot.

Also could be a dirty injector, have you run any fuel system cleaner through it?

 

[sgesbeck]

The MAP should be good.

Measure the resistance of the injectors and see if number 3 is different or if it is different when hot.

Also could be a dirty injector, have you run any fuel system cleaner through it?

I replaced the Fuel Injectors back in 2/2024 with Bosch III Upgrade remanufactured injectors from CS Performance Injectors. I'll check the resistance later today. My fuel economy is pretty good at 18.5 mpg. I always reset the trip odometer when I refill and I always refill when near empty. I started doing this years ago and it is a good way to keep track of changes in fuel economy that could indicate an issue.

Haven't run any fuel system cleaner since replacing the fuel injectors.

 

[sab]

All your codes can be caused by misaligned cam and crank pulses. I covered some of the "why?" in this thread. Here's an excerpt:

The PCM is keeping track of the crankshaft’s position and the camshaft’s position during each revolution and determining when to fire each injector and spark plug based upon those sensor signals (the crank sensor triggers the spark plugs and the cam sensor triggers the injectors). Small variations in the output signal of each individual sensor become problematic to the PCM, as it can cause the PCM to misinterpret those positions, which can cause serious engine problems.

In addition to using the signals to fire injectors and spark plugs, the PCM also monitors them and looks for problems. For instance, the P03XX codes for misfires are triggered when the PCM sees a slight change in the time between two cylinders firing because the crank actually speeds up slightly with each cylinder’s firing, and if a cylinder doesn’t fire, the PCM can detect that from the cam and crank sensor signals because the crank fails to accelerate at that point in the crank’s rotation.

To add further information, out-of-sync cam and crank signals can both cause actual misfires and make the PCM think misfires are occuring, even if they aren't (a false DTC trigger.) Rather than continuing to throw money at parts, why not invest in a bi-directional scan tool and re-sync the cam and crank positions in the PCM? The link posted at the beginning of this post explains how to do it with a DRBIII, but if you continue down the thread, you'll see others have had good luck with other, cheaper devices.

Also, this post I made explains why it's a good idea to manually adjust the OPDA position prior to running the sync, especially if you have a aftermarket sensors:

Post in thread 'Post ODBA replacement cylinder 1 misfire (reoccurring every 150 miles)'

Oct 13, 2024

What brand did the shop replace the OPDA and crank sensor with?

I'm not sure the brand...My guess is an OEM one though.

Doubtful - the Mopar OPDA has been discontinued for years.

Anytime the OPDA is changed, the Relearn procedure is good to do. Also, if the sensor was replaced (especially with an aftermarket sensor), you'll have best luck by manually adjusting the position of the OPDA to get the Cam/Crank Difference as close to zero as possible before performing the Relearn procedure. The aftermarket sensors don't seem to be as precise as the OEM sensors (which are very...

• sab

• 

Good Luck!

 

[sgesbeck]

All your codes can be caused by misaligned cam and crank pulses. I covered some of the "why?" in this thread. Here's an excerpt:

The PCM is keeping track of the crankshaft’s position and the camshaft’s position during each revolution and determining when to fire each injector and spark plug based upon those sensor signals (the crank sensor triggers the spark plugs and the cam sensor triggers the injectors). Small variations in the output signal of each individual sensor become problematic to the PCM, as it can cause the PCM to misinterpret those positions, which can cause serious engine problems.

In addition to using the signals to fire injectors and spark plugs, the PCM also monitors them and looks for problems. For instance, the P03XX codes for misfires are triggered when the PCM sees a slight change in the time between two cylinders firing because the crank actually speeds up slightly with each cylinder’s firing, and if a cylinder doesn’t fire, the PCM can detect that from the cam and crank sensor signals because the crank fails to accelerate at that point in the crank’s rotation.

To add further information, out-of-sync cam and crank signals can both cause actual misfires and make the PCM think misfires are occuring, even if they aren't (a false DTC trigger.) Rather than continuing to throw money at parts, why not invest in a bi-directional scan tool and re-sync the cam and crank positions in the PCM? The link posted at the beginning of this post explains how to do it with a DRBIII, but if you continue down the thread, you'll see others have had good luck with other, cheaper devices.

Also, this post I made explains why it's a good idea to manually adjust the OPDA position prior to running the sync, especially if you have a aftermarket sensors:

Post in thread 'Post ODBA replacement cylinder 1 misfire (reoccurring every 150 miles)'

Oct 13, 2024

What brand did the shop replace the OPDA and crank sensor with?

I'm not sure the brand...My guess is an OEM one though.

Doubtful - the Mopar OPDA has been discontinued for years.

Anytime the OPDA is changed, the Relearn procedure is good to do. Also, if the sensor was replaced (especially with an aftermarket sensor), you'll have best luck by manually adjusting the position of the OPDA to get the Cam/Crank Difference as close to zero as possible before performing the Relearn procedure. The aftermarket sensors don't seem to be as precise as the OEM sensors (which are very...

• sab

• 

Good Luck!

SAB - Great information! Thanks for the explanation of how the out of synch condition can cause the misfires, or in my case the false misfires. I'm heading up into the canyon this morning and I'll do the PCM relearn procedure that you and BigFootNM described by touching the positive lead to the negative post. I'll post results when I get back.

 

[sab]

... I'll do the PCM relearn procedure that you and BigFootNM described by touching the positive lead to the negative post. I'll post results when I get back.

To reiterate my last post, if you don't have Mopar sensors, that action alone may not be successful. Aftermarket sensors are not built as precisely and often require a manual rotation of the OPDA while monitoring the "Cam Crank Difference" variable in the datastream to set that variable as close to zero as possible. It's explained more in that thread (see the "If You Rotate Your OPDA" section in the first post).

Edited to add: With the quality of everything in the toilet these days, even a Mopar sensor may require a manual rotation to get it to work.