Wheel speed sensor , ABS module or possessed

Donut707

Donut707

Member
On my drive into work this morning the jeep had an interesting fault . The speedo was erratic and the all ABS, EAS and ABS lights were flashing and the chiming. I had a abs light on intermittently a while ago but never long enough for a code to be detected ( odd) . I'm suspecting one or more wheel speed sensors , or the ABS module has or is begging to fail.
2008 JKU
 
Donut707 said:
On my drive into work this morning the jeep had an interesting fault . The speedo was erratic and the all ABS, EAS and ABS lights were flashing and the chiming. I had a abs light on intermittently a while ago but never long enough for a code to be detected ( odd) . I'm suspecting one or more wheel speed sensors , or the ABS module has or is begging to fail.
2008 JKU
Click to expand...
auto parts store should be able to read the codes if you don't have a reader, should be able to tell you which sensor is bad if that's the issue but
could also be cut/chewed wires (rodents) or tone ring.issue.

Don't recall the sequence but you can also do a key sequence to show the codes on the dash, I believe where the mileage indicator is.
 
My jscan didn't detect anything . I will double check the battery connections. My local shop has a snap on scanner they let me play with , so ill swing by there at lunch to see if it picks anything up . ive has wheel speed sensors and even a bacd unit bearing before give a abs light on steady. the speedo all erratic was a first , the jeep drove fine no other issues or indications of anything else being wring.
thanks for all the input , ill report back what i find
 
jscan won't pick up a loose lead. The battery leads have conical nuts that create compression on the clamps. If you've installed something like a radio or compressor and attached a ring terminal between it and the clamp, that would prevent it from tightening it well. Of course, that is just one example of what can cause a loose lead. For the most part, the lead will be fine but a bump in the road can cause a momentary separation and that will cause the erratic lights going on and other issues you see. Not saying this is what you've got going on but I have personally seen this happen and on lots of JK's including my old 2012 that I used to have.
 
What @wayoflife said. I had a similar issue a while back and it was literally just the negative terminal lead. Moved my accessories to a different post and tightened the conical nut back down. Hasn't happened since.

I did also have the ABS and traction light on solid on a separate occasion, but not flashing or with a wild speedo. That turned out to be the wheel speed sensors.
 
jeeeep said:
auto parts store should be able to read the codes if you don't have a reader, should be able to tell you which sensor is bad if that's the issue but
could also be cut/chewed wires (rodents) or tone ring.issue.

Don't recall the sequence but you can also do a key sequence to show the codes on the dash, I believe where the mileage indicator is.
Click to expand...
Also this ^

Turn the key three times to the accessory position quickly. Dashed line will pop up where the odometer is and show you the currently stored codes followed by "done"
 
Agreed on battery terminal. The speedo jumping all over the place is the most consistent symptom that I have had on my JK, caused by the loose terminal.

Even if the negative terminal seems pretty tight, I take it off and reinstall it, and the problem is solved.
 
At lunch i was able to verify the battery terminals were tight . On my drive over to m shop it finally threw a dtc PO537 brake switch stuck on ... when i hooked up the matco scanner , it read the P0573 brake switch and a pending P0501 vehicle speed sensor 1 performance. we inspected the wheel speed wiring and sensors , looked for obvious sign of any other wiring issue and couldnt find anything. I cleared the codes and the jeep drove fine back to work ... so i will continue to monitor / thanks for all the input ..
 
I’m still gonna say loose battery as stated. They will actually feel tight by hand but the OEM terminals suck. And a faulty ground can throw some random codes for sure. Seeing the tac drop like it is and lights flashing all crazy screems ground wire. Ive had the same issue. A faulty sensor will just throw a code or the traction control light on the dash.
 
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