1991 XJ Code 22 Coolant Temperature Sensor

[mahanja]

I'm getting a Engine Coolant Temperature Sensor Code 22 consistantly. I read the wires from the ECU to the sensor and they read good. I recently installed a new sensor so I assumed I got a bad one but the resistance when cold and hot are good. Any ideas?

 

[92DripCherokee]

maybe poor grounding, if you wrapped the sensor in teflon tape it could be floating and ungrounded.

otherwise it could be a faulty part.

OEM pn is 33004281

 

[mahanja]

I hooked up the old sensor and it remains. No teflon tape. The only reason I replaced it is that the connector was broken on the sensor. But it didn't have the code before. WTF?!?

 

[92DripCherokee]

have you tried disconnecting the negative battery terminal to clear the code?

 

[mahanja]

Yep. Left it off two different times for over 5 min each. Just read the sensor again. 9k ohms cold, 1.25k ohms hot. I am running a 180 deg thermostat since I live in the Mohave Desert so those readings should be correct right? I also re-read the wires all the way to the computer for continuity. They check good. The code latches within 5 seconds of starting. Anyone need/have anymore info?

 

[mahanja]

I went ahead and bought another sensor and hooked it up. Same situation. Tried jumpering the two wires together to see if it would trick the code to disappear. No such luck. I reset the computer for 10 min in between each check. The code latches even before I turn it over. Any info out there?

 

[89CherokeePioneer]

I'd venture to say a bad ECM in that case-if the ECM is setting the code within five seconds of a cold start (the sensor wouldn't have even reacted in time)

 

[mahanja]

Well, now the whole d@mN thing won't start. And I'm getting codes 12, 22, 22, 55. What the heII? It spits out 22 twice? The way it is acting other than the codes, I'd say CPS. I went through 3 of them on my '94 XJ with manual. It died on me while I was driving around yesterday. I started it up again and it made it 4 more blocks before stuttering and trying to die. It finally did and took a while to start up again. (About 3 min). I guess I'll start the "no start" procedures tonight. UGH!!!

 

[mahanja]

It ended up being the Coolant Temp Sensor plug. It had continutity but obviously did not have a good connection. I ended up bending the connecting feet with a scribe and now it works 5.0. The No Start was caused by the coil connector backing out. The tab is broken so I zip tied it. Back on the road!