Hey guys I pulled the codes from my d and got 2 codes. p0138 and p1492. So the 02 senor is prob eating my gas mileage so I was wondering which sensor it is. from what I read its the one after cat. Right? also what do i have to do with code p1492 Ambient/Battery Temp Sens Volts Too Hi?

Andrew


ohh and I have a 98 slt witha a 360.

 

P0138 is bank 1 sensor 2 so yup it's the one after the cat. That sensor doesn't do anything for the fuel mixture though, it only monitors that the cat. is working.

The other code is for one of your temperature sensors that's just shorted inside, cheap stuff to replace. Either the black sensor on the front of the car just to the right of the left headlight, or your battery temp sensor which is under the battery platform. The battery sensor is actually pretty important because that's checked for various things like weather or not to run in open or closed loop. So your gas mileage may be bad because of your battery sensor and not the O2 sensor.

 

Indeed and +1 Evon. I agree that bad MPGs are to be looked within the P1492 issue, and the P0138 issue is probably simply a dead sensor, however it could very well be a P0138 issue killing your MPGs.

The definitions of both of them are literally:

P0138- 1/2 O2S Shorted To Voltage
P1492- Ambient/Battery Temp Sens Volts Too Hi

My first question is do you have an overhead display module that indicates outside air temperature, because if not the only place to look is the Battery Temp Sensor. If you do have the display, I would say start by replacing the Battery Temp sensor and the downstream O2 sensor first and foremost.

If none of that helps either codes (I'm very sure it will) check both the fuel pressure at the rail because you could have high fuel pressure with that code, and replace the Ambient Temp Sensor.

 

I pulled the P1492 code on my 2000 1500 Sport 5.9L AT 4X4, yesterday and I understand what it is, where the APLSOL sensor is located and what it's for. However, I won't be able to replace it til next week. Is it a critical item that needs to be repaired immediately, or can I still drive the truck til then without worry of any damage? The MIL isn't lit up. The battery is good, and the alternator seems to be charging fine.

 

No harm done driving it like that. If your MIL light is off but you still pulled a code, it's probably a pending code which will either fix itself or light up the MIL if it's a real problem.
I'd just keep an eye on your gas mileage, the battery temp sensor does a whole lot more than you think, it's also a sensor the PCM monitors to decide whether to run in closed or open loop.

 

Okay, thanks.

 

Anybody know if p1492 (Ambient/Battery Temp Sens Volts Too Hi) is a hard code? I had my battery sitting out while I swapped out fenders and it got hot in the summer heat. I figured the battery being hot is what gave me the code. I can't reset it now. Would maybe forgetting to put back a ground set it off?

 

It was most likely that it was over heated. The code cleared and everything is fine. The PCM most likely won't remember it.