Help! Check engine light - Multiple DTC’s

[IanNubbit]

This is 100% Can bus issue. Also, you SHOULD be okay since it’s the same concern multiple times. And trust me dealers aren’t smart enough to “perform small repairs until your out of warranty”

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[ShadowsPapa]

I'd imagine they have some scanner that could scan for codes that have been triggered even though they are not present. Made an appointment for next week on Monday , lets hope the dealership can find out what's going on. It's frustrating to be out somewhere when this error code is triggered and I can't use 4wd ugh.

No, if it's just transient, it won't be stored, and may not trigger a light.
The only way to catch such things is live logging, freeze frames.
I've run into this with misfires - if it doesn't request the MIL or a code be stored, it's not going to be findable. Some things are logged, some are not.

Here's a case where there was a clear misfire, no light, no code stored. I captured it live.
Dealer tried and tried and could not find any DTC............ no trace of the misfire once I got it there.

Error code: P0303
Cylinder 3 ignition failures
Test not complete
Error intermittent
Error warning lamp not requested
CARB Freeze Frame:
___________________
Fault code: P0303
PCM Mileage since MIL On: 0.00 miles
PCM Odometer: 950.27 miles
Open Loop - Bank 1: No
Closed Loop - Bank 1: Yes
Open Loop due to Driving Conditions - Bank 1: No
Open Loop with DTC - Bank 1: No
Closed Loop with DTC - Bank 1: No

 

[ShadowsPapa]

I used my own code reader and only saw 6 codes, but the dealer downloaded 53.

Depends on the module and what your device has access to. Many only read engine faults.

 

[SF_E60]

No, if it's just transient, it won't be stored, and may not trigger a light.
The only way to catch such things is live logging, freeze frames.
I've run into this with misfires - if it doesn't request the MIL or a code be stored, it's not going to be findable. Some things are logged, some are not.

Here's a case where there was a clear misfire, no light, no code stored. I captured it live.
Dealer tried and tried and could not find any DTC............ no trace of the misfire once I got it there.

Error code: P0303
Cylinder 3 ignition failures
Test not complete
Error intermittent
Error warning lamp not requested
CARB Freeze Frame:
___________________
Fault code: P0303
PCM Mileage since MIL On: 0.00 miles
PCM Odometer: 950.27 miles
Open Loop - Bank 1: No
Closed Loop - Bank 1: Yes
Open Loop due to Driving Conditions - Bank 1: No
Open Loop with DTC - Bank 1: No
Closed Loop with DTC - Bank 1: No

Ugh not what I wanted to hear and the reality of trying to trigger this code is impossible. Drove locally at all times of the days with code not being triggered. Took a road trip this past weekend 600 mile round trip and code triggered when I was 15min from camp. Couldn't use my 4wd. When it was time to head back code was gone and nothing was triggered on the way home.

 

[IanNubbit]

Looked at this again today. Can-C is 100% loosing coms with ABS module intermittently. Might be a pinch or kinked twisted pair front the ABS. My guess would be the ground for the ABS module, loose or dirty grounds tend to be pretty common these days (Stellantis has dropped the ball on assembly line control). Check here and see if there is corrosion, paint on the eyelet, or it you can rotate the wire at all by hand, should be rock solid snug with no chance of moving it with the nut tight.

 

[ShadowsPapa]

Check here and see if there is corrosion, paint on the eyelet, or it you can rotate the wire at all by hand, should be rock solid snug with no chance of moving it with the nut tight.

I always suggest for checking of connections - don't just look, take it apart, then look at where the parts make physical/mechanical and electrical contact, and clean them.

I've had too many people come back and say "I looked and they are clean" only to actually have voltage drop at that point - enough to cause trouble but not be visible. Oxide films are thin.........
Sometimes the act of loosening a nut, then moving the wire a few degrees back and forth, and tightening it up again is enough.

 

[SF_E60]

***Update*** Thought I'd give an update to the thread since I picked up the jeep yesterday from the dealership. Tech found code U0418 Implausible data received from brake system control module 1, U140A Implausible right front wheel speed signal received, C0034-1D right front wheel speed sensor-circuit current out of range, C0034-2F right front wheel speed sensor signal erratic, U0415-00 invalid data received from anti-lock brake system (ABS) check control module "A". The tech then inspected the sensor wire for damages and there no visible damage. Tech then drove the jeep and checked the data and the RF sensor wasn't reading any speed when driving. Tech removed the sensor and measured for resistance at the connector and found the sensor had a open circuit. Tech proceeded to inspect the wheel bearing for excessive play and the bearing failed. Parts ordered under warranty and replaced.

Parts that were replaced were the Hub & brake + the front wheel speed sensor .

Hoping (ABS) light doesn't come back again.

 

[stephhhanie]

All the same lights you mentioned came on in mine. Problem is, my brake was locked too so I was unable to press the brakes to start the engine or even shift out of park. I had to have my Jeep towed to the dealer. I only have less than 4000 miles and just purchased it earlier this year. I’m afraid of being jerked around with the dealer too as I already was with a different issue I was having. Do you have an update with why all these lights came on?

 

[stephhhanie]

***Update*** Thought I'd give an update to the thread since I picked up the jeep yesterday from the dealership. Tech found code U0418 Implausible data received from brake system control module 1, U140A Implausible right front wheel speed signal received, C0034-1D right front wheel speed sensor-circuit current out of range, C0034-2F right front wheel speed sensor signal erratic, U0415-00 invalid data received from anti-lock brake system (ABS) check control module "A". The tech then inspected the sensor wire for damages and there no visible damage. Tech then drove the jeep and checked the data and the RF sensor wasn't reading any speed when driving. Tech removed the sensor and measured for resistance at the connector and found the sensor had a open circuit. Tech proceeded to inspect the wheel bearing for excessive play and the bearing failed. Parts ordered under warranty and replaced.

Parts that were replaced were the Hub & brake + the front wheel speed sensor .

Hoping (ABS) light doesn't come back again.

What do any of those codes mean?! So basically they had to replace the sensor and it fixed the issue of all the lights coming on?

 

[ShadowsPapa]

What do any of those codes mean?! So basically they had to replace the sensor and it fixed the issue of all the lights coming on?

In HIS case it did.
But it's extremely assuming and not helpful to "assume" that what fixed his will fix another.
Maybe, maybe not.
The codes were all dealing with ABS, stability control, wheel sensor input and so on.
These do a POST, power on self test. If they don't see a connection through certain sensors, it throws an error code.
When you start to move, and get to about 7 mph, another ABS test is done - sometimes people hear it happen - and if the results don't make sense to the ABS module, more codes may be triggered.
Not communicating with a sensor can mean the sensor itself, the tone ring the sensor senses from could be muddy, dirty, the wire TO the sensor could be bad - pinched, pulled by someone not being careful installing a lift or springs, any connection between the ABS module and the sensor it can't read from or get a response from could be open or bad.
A sensor is just one link in a chain from ABS module to the wheel area.
Sometimes those wires get damaged by people in a hurry or not taking care when dropping the axle for spacers or taller springs.
In my case on an older Jeep - it was the ABS module itself that was bad - a connection within. The light came on as soon as it was doing POST - it wasn't able to communicate with the wheel sensors, they were all fine, all good, as was all of the wiring.

You need to know what codes were involved in YOUR case. You can't say they were the same unless the codes line up. Maybe they will be, but.......
It's not common for sensors to go bad unless there's another issue - like in the case of the other guy. Normally wiring and connections are the first things to look at. There are Jeeps out there that are 20 years old, over 100,000 miles, with all original wheel sensors.

 

[stephhhanie]

In HIS case it did.
But it's extremely assuming and not helpful to "assume" that what fixed his will fix another.
Maybe, maybe not.
The codes were all dealing with ABS, stability control, wheel sensor input and so on.
These do a POST, power on self test. If they don't see a connection through certain sensors, it throws an error code.
When you start to move, and get to about 7 mph, another ABS test is done - sometimes people hear it happen - and if the results don't make sense to the ABS module, more codes may be triggered.
Not communicating with a sensor can mean the sensor itself, the tone ring the sensor senses from could be muddy, dirty, the wire TO the sensor could be bad - pinched, pulled by someone not being careful installing a lift or springs, any connection between the ABS module and the sensor it can't read from or get a response from could be open or bad.
A sensor is just one link in a chain from ABS module to the wheel area.
Sometimes those wires get damaged by people in a hurry or not taking care when dropping the axle for spacers or taller springs.
In my case on an older Jeep - it was the ABS module itself that was bad - a connection within. The light came on as soon as it was doing POST - it wasn't able to communicate with the wheel sensors, they were all fine, all good, as was all of the wiring.

You need to know what codes were involved in YOUR case. You can't say they were the same unless the codes line up. Maybe they will be, but.......
It's not common for sensors to go bad unless there's another issue - like in the case of the other guy. Normally wiring and connections are the first things to look at. There are Jeeps out there that are 20 years old, over 100,000 miles, with all original wheel sensors.

Thank you for your explanation.

The dealer had to replace my catalytic converter a week ago. When they changed it do you think they may have accidentally touched a wire from underneath? Or is it mostly just a technical system error? My car was towed to the dealer but they didn’t have any availability until Wednesday, so I’m just trying to get an idea what may have caused this.

 

[Rex3rd]

To have that many dtc, it's definitely a loose/bad connection somewhere, or short to ground. I had a similar instance after going a lil to deep too many times. Had a wet connector that wouldn't let me start vehicle. 1 week later after drying out, I was good, cleared codes, and drove fine... till I got sand in motor at a much later date.

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