[natedubz]

Hello!

I have a 2010 R/T w/ BBK shorty headers, 22s (no TPMS) and a muffler delete (the rest is stock). Shortly after I bought it (heavily used), the engine overheated and I replaced all the gaskets, intake manifold, and resurfaced the cylinder heads, which has fixed that problem. A "P0198 - Engine Oil Temperature Sensor Circuit High" code came on (the sensor is a thermistor whose resistance is inversely proportional to oil temp, the circuit has a 5V reference voltage), meaning (I think!) that the oil is either frozen (nope), or the circuit is likely open.

The code is permanent, so it's stored in the PCM and can only be cleared by the PCM itself, not any OBD2 devices.

I replaced the sensor, and drove it for about 250 miles, that did not fix it. I inspected the wires (including with a endoscope to check the hard to see spots), and did not see any wires that were exposed or worn, or any wire bundles whose cover was worn.

I replaced the wiring harness connector and tested the sensor/connector with a multimeter and got readings that fluctuated between about 30 - 175 ohms (Idk if fluctuating readings is normal or if my multimeter sucks, it's been a minute since my high school physics days) which I believe is a good reading for the EOT sensor at ambient temp.

Right now, I have to drive it some more to see if that will clear the code. I called a dealership and chatted with a tech (who was very kind to take my call and just talk!), and he couldn't give me any other advice besides taking it in and having them connect their witech and see what reading the PCM is getting for the EOT sensor circuit in real time, which is about $200.

While I'm putting another 200ish miles on this and keeping my fingers crossed, does anyone know how to get the drive cycles done faster, or how to get a EOT sensor circuit reading (at or near the PCM, as that would tell me if the issue is the wiring between the sensor and the PCM or at/in the PCM itself)? I've searched for a pinout (no luck), and already tried a few OBD2 scanners, including AlfaOBD which has the most accessible data that I could find, but it does not read the EOT sensor (don't think any consumer products do).

Thanks for reading this short novel, and TIA for any advice or help!

 

[Rockster]

Don't think special drive cycles are required to clear the code. Just X number of warm up cycles with the error not present. This can range -- my experience with other brands of cars -- from 3 to lots... The lots error code was a P0430 (converter operating below efficiency threshold) and rather than clearing the code -- which I had done a number of times before and then going months without it appearing -- I decided to just drive the car and see how long it took the ECU to clear the code and extinguish the CEL. The CEL eventually went dark. I didn't count the warm up cycles but I'd estimate half a zillion...Well, not quite. But at least 30.

 

[natedubz]

Thanks. I've been tracking miles, and I'm up to 130+. I haven't counted warm up cycles, but it's gotta be at least 15. I'll keep trying.

I'm feeling kind of defeated. It could be a wiring problem, and I could test the whole circuit if I could find a pin out or a reliable diagram. Then at least I'd know if I have to reflash/replace the PCM or not.

 

[Rockster]

Thanks. I've been tracking miles, and I'm up to 130+. I haven't counted warm up cycles, but it's gotta be at least 15. I'll keep trying.

I'm feeling kind of defeated. It could be a wiring problem, and I could test the whole circuit if I could find a pin out or a reliable diagram. Then at least I'd know if I have to reflash/replace the PCM or not.

You should be able to clear the code render it inactive. With some codes the code also shows up as a permanent code that can only be cleared by the engine controller if the error does not reappear and after X number of warm up cycles.

In clearing the code the CEL should go dark.

If the CEL is back on and the code is the same then the error is being detected. The error condition must be addressed.

 

[SweetT]

This is probably elementary but being how I am guilty of it. Make sure the hole the sensor is in is clear of any cooked engine oil gunk/ build up. It will be stuck in place and sitting there getting hot from not moving and you'll be losing you damn marbles trying to figure out what's going on.
Especially since you bought it "heavily used" people don't always keep up in maintenance and oil changes is one of the biggest offenders. Synthetic oil is pretty awesome stuff. But the additive in it that helps to suspend particles breaks down fairly quickly especially with above normal heat.

 

[natedubz]

You should be able to clear the code render it inactive. With some codes the code also shows up as a permanent code that can only be cleared by the engine controller if the error does not reappear and after X number of warm up cycles.

In clearing the code the CEL should go dark.

If the CEL is back on and the code is the same then the error is being detected. The error condition must be addressed.

I've tried clearing the codes several times, the CEL has never gone dark. My understanding is this is a permanent code that can only be cleared by the ECU/PCM

 

[Rockster]

I've tried clearing the codes several times, the CEL has never gone dark. My understanding is this is a permanent code that can only be cleared by the ECU/PCM

A permanent code is one that can only be cleared by the ECU. Provided the engine experiences a sufficient number of warm up cycles with the error condition not reappearing.

But if one clears the code -- which makes it is no longer active -- and then upon engine restart the CEL is on and the code is present that's not a permanent code, per se, but an active code that is active because the error condition is present upon engine restart.

 

[natedubz]

I should have noted that I use a Z Automotive BurnBox G1 every now and then -- I wonder if that has been known to cause PCM issues? I'll go check their website/support and see what I find.

 

[natedubz]

Question for any experts out there!!!

(background) I've been reading in some other forums about various testing for P0197 (which is similar to my P0198 code. P0197 = circuit reading low, P0198 = circuit reading high), and saw someone post a schematic for a Charger R/T, which I assume is similar if not the same for the Challenger.

Here's my two part question, if I disconnect the wiring connector from the EOT sensor, can I test the ground and voltage signal from the two wires to determine if there is a wiring issue and will that essentially rule out everything but the PCM?

(I've already replaced and measured the sensor and connector, they are both good)

 

[natedubz]

Question for any experts out there!!!

(background) I've been reading in some other forums about various testing for P0197 (which is similar to my P0198 code. P0197 = circuit reading low, P0198 = circuit reading high), and saw someone post a schematic for a Charger R/T, which I assume is similar if not the same for the Challenger.

Here's my two part question, if I disconnect the wiring connector from the EOT sensor, can I test the ground and voltage signal from the two wires to determine if there is a wiring issue and will that essentially rule out everything but the PCM?

(I've already replaced and measured the sensor and connector, they are both good)

Well, I disconnected the wiring harness connector from the sensor and measured the connector nodes with a multimeter, with the ignition on/engine off and with the engine on. Both times the voltage came in way under 1V, roughly .004V and .007V...so...I think it's safe to say there's a wiring short somewhere.