Online reference on DTC codes?

[c5dura]

Is there a resource online for looking up DTC codes? My SES light has come on 4 times already and I only have 1300 miles on the truck.

I called OnStar but they are pretty clueless about the specific codes and I don't have my service manuals yet.

Anyway, here are the codes that set so far:

Date Miles Code Description
8/29 1150 P0181 Fuel Temp. Sensor 1 Circuit Performance H H P
8/31 1266 P1683 Driver 5 Line 3 H H P
8/31 1268 P1683 Driver 5 Line 3 H H P
8/31 1289 P1683 Driver 5 Line 3 H H

[mdrag]

c5dura,

Try this site for an explanation of specific OBDII codes:

www.obdii.com

[mdrag]

c5dura,

From www.obdii.com/codes.asp :

General Motors P0181 Fuel Temp. Sensor 1 Circuit Performance

General Motors P1683 Driver 5 Line 3

Really doesn't help... Here are the descriptions from the manual:


DTC P0181

Circuit Description:
The fuel temperature (FT) sensor is a thermistor. The engine control module (ECM) supplies the FT sensor a reference voltage of 5 volts...

Conditions for Running the DTC:
DTCs P0112, P0113, P0182, P0183, or P1683 are not set.....

Conditions for Setting the DTC:
The fuel temperature and the IAT are more than 10

[Mic]

IIRC,

I believe that there has been some occurrances where the sun can heat up the airbox ( hence the IAT ) when parked in extreme sun conditions. then when started the PCM 'sees' the fuel temp and the incoming air temp are WAY out and throw a code.

[c5dura]

Thanks for pulling this info for me mdrag!

I'll print this out and take it with me to the dealer on Tuesday. That second code set again twice today.

Btw, that first code, P0181 was set about 15 minutes into a drive at 9 pm or so, so in my case I doubt that there were external factors involved such as sun heat.

[3TV]

How do I find out which codes have been set on my truck? The reason I ask is because my truck is just two weeks old and is at the dealers service dept right now to have a faulty TCM (transmission control module) replaced. What I noticed when driving the truck towing an 11,200 lb. trailer, was that it inappropriately upshifted from 4th to 5th gear while pulling a grade, and then would not shift down to 4th gear again, even after stomping the gas pedal all the way to the foor. The truck proceeded to continue lugging the engine, and slowing down, until the tachometer read just 1500 RPM, and it remained in 5th gear despite seriously lugging the engine. I finally downshifted manually with the shift lever, and when doing that I noticed that the transmission gear position indicator was not working, and then that the transmission temperature gauge was not working. I had tried using the overdrive-off button, and switching back and forth between regular and tow/haul modes before manually downshifting the transmission, and they had not worked either.

Is there some way I could have checked to see if a code had been set, and which one, before taking the truck in for repairs? I had thought a wire had come disconnected under the truck so had my wife watch the instrument panel while I gently jostled the wires down by the top of the transmission, and while doing this a "check engine" light came on. Does that mean that jostling the wires had set another code? And if so, could I have checked to see which code had been set?

I am concerned that there is more wrong with my truck than just the TCM. I think there may also be a bad wiring harness that the dealership is going to miss.

Thanks,
3TV

[c5dura]

3TV, I used a program called Autotap that I run on my laptop. The laptop then connects to the truck via its serial port through an adaptor that connects to the ODBII port on the truck. This port is located under the dash near the driver's door.

This is also where the dealer would connect the scan tool to pull these codes.

Autotap will do a lot more than just pull codes and clear them. It will monitor all kinds of variables such as turbo boost, air intake temp, coolant temp, etc. You can even log all these variables and analyze them later. Its a great tuning tool.

For more info, you can check out http://www.autotap.com.

[mdrag]

3TV,

You need a scan tool to read the DTC's, such as the Tech2, AutoTap, Auto Xray, etc. There are others - and the prices range from $100 or less to more than $2.5K for the Tech2...

The old trick of using a jumper wire to read the codes will not work on these trucks...

mdrag

[SDWA]

The Tech2 is only $2500??? I thought it was like $7000... Can the general public get the software updates for it?

Scott

[mdrag]

SDWA,

Here's a link for the basic Tech2 model OTC 3625 at $2.7K:

www.automotivetools.com/cgi-local/SoftCart.exe/online-store/scstore/p-OTC-3625.html?L+scstore+jxcy1758ff596959+1033681198

The Deluxe model with additional 3-in-1 software OTC 3627 is listed at $3.2K :

www.automotivetools.com/cgi-local/SoftCart.exe/online-store/scstore/p-OTC-3627.html?L+scstore+jxcy1758ff596959+1015251112

I believe OTC will update the software for 1 year if you send the flash memory card back to them. After that, make friends with someome at the dealership... ;)

mdrag

[SDWA]

Just ordered one. I never knew they were so inexpensive! Now I have to find a buddy at a dealership!

Scott

[SDWA]

Just kidding. I would consider going in on one with a group purchase/use deal, though!

Scott