SES light Codes P0740, P0785, P1860

[djkurious]

I am a proud owner of a 1999 Chevrolet Tahoe 5.7 LT.

I got into my truck today and the SES light came on. So I tried to reverse it out of my driveway, and it acted as if reverse was neutral, NO REVERSE. So I pushed it out the driveway and put it in drive for that wonderful trip to AutoZone. On my way there, I noticed that the shift point from 1st gear to 2nd was in the 3000 RPM's range (unusual). The rest of the shift points were ok, but it would not go into overdrive. So I got to AutoZone and the codes were P0740, P0785, and P1860. I researched the codes on the internet and came up with this:

 

P0740 - TCC enable solenoid circuit electric

P0785 - 3 - 2 shift solenoid circuit electrical

P1860 - TCC PMW Solenoid circuit electrical

 

Now I also read that the cause of this would be a incorrectly installed aftermarket remote start system (or alarm). Now I do have a aftermarket remote start system by the name of AutoPage RS-750LCD. I had it installed by a very reputable dealer that the alarm system referred me to (CarTronics). Also, the remote start system has been installed for 4 years, 8 months to be exact. I have never had a problem with the remote start.

 

Troubleshooting:

 

The only troubleshooting I have done was replaced the transmission fuse. The fuse was not blown, I just like to make sure of things.

 

Also, I have read on this forum that it could be the ignition wiring harness. Now before I go and order one for $80 bucks, I wanted to check with you guys. Is this something that I need to just drop off at the dealer and get a hole punched in my pocket, or is this something I maybe can fix myself. My experience with automobiles is not that of a mechanic, but i have fixed various things on my truck before (replaced shocks, alternator, spark plugs, wires, brakes, and things of that nature).

 

Any advise will work!

[djkurious]

Ok thanks. I went ahead and subscribed to Alldata.com. Good info! If anyone else needs info from Alldata on my same truck, PM me.

[GM-Tech]

Definitely sounds like an ignition switch to me. Here's a TSB related to this..

 

 

Subject: MIL On, Transmission Stuck in Second or Third Gear, IPC Inoperative, DTCs P0740,P0753,P0758,P0785,P0787,P0973,P0976,P1860,P2761,P2764 and/or P2769 Set (Verify and Repair Source of Voltage Loss #01-07-30-002E - (09/23/2005)

 

 

 

Models: 2006 and Prior GM Passenger Cars and Light Duty Trucks

 

2005-2006 HUMMER H2

 

2006 HUMMER H3

 

2005-2006 Saab 9-7X

 

with 4L60-E, 4L65-E, 4L80-E or 4L85-E Automatic Transmission (RPOs M30, M32, M33, MT1, MN8)

 

 

 

 

--------------------------------------------------------------------------------

 

This bulletin is being revised to update model years, add additional models and add additional diagnostic information. Please discard Corporate Bulletin Number 01-07-30-002D (Section 07 -- Transmission/Transaxle).

 

 

--------------------------------------------------------------------------------

 

Condition

Some customers may comment on one or more of the following conditions:

 

• The Malfunction Indicator Lamp (MIL) is ON.

 

• The transmission is defaulted to second gear (4L80/85-E).

 

• The transmission is defaulted to third gear (4L60/65-E).

 

• The instrument cluster is inoperative.

 

Upon investigation, one or all of the diagnostic trouble codes (DTCs) P0740, P0753, P0758, P0785, P0787, P0973, P0976, P1860, P2761, P2764 and P2769 may be set depending on the vehicle.

 

Cause

The most likely cause of this condition may be a loss of voltage to the transmission solenoid power supply circuit.

 

This condition may also be the result of an incorrect installation of an aftermarket electronic device such as a remote starter or alarm system.

 

Correction

Important: If the vehicle is equipped with an aftermarket electronic device and the DTCs are being set when the device is being used, verify that the appropriate fuse is being supplied battery voltage during operation. If voltage is not present at this fuse, these DTCs will be set due to lack of voltage at the solenoids. This condition is most likely to occur with an incorrectly installed remote starting system. If this is the case, refer the customer to the installer of the system for corrections. ANY REPAIRS DUE TO AFTERMARKET INSTALLATION OF ACCESSORIES IS A NON-WARRANTABLE ITEM.

 

With the ignition switch in the RUN position, test for battery voltage at the circuit fuse in the transmission solenoid power supply circuit. Refer to the appropriate SI Document for the transmission solenoid power supply circuit information.

If battery voltage is present at the fuse, inspect the ignition voltage circuit between the fuse and the transmission for possible opens.

If battery voltage is not present at the fuse, test for continuity between the fuse and the ignition switch. If NO continuity is between the fuse and the ignition switch, repair the open in that circuit.

If you have continuity between the fuse and the ignition switch, the most likely cause is the ignition switch. Replace the ignition switch using the appropriate Ignition Switch Replacement procedure in SI. Refer to group number 2.188 of the parts catalog for part description and usage of the ignition switch.

Warranty Information (excluding Saab U.S. Models)

For vehicles repaired under warranty, use:

 

Labor Operation

Description

Labor Time

 

N6630

Wiring and/or Connector, Transmission - Repair

Use published labor operation time

 

 

Warranty Information (Saab U.S. Models)

For vehicles repaired under warranty, use:

 

Labor Operation

Description

Failed Object

Fault/Reason Code

Location Code

Warranty Type

Repair/Action Code

Labor Time

 

3711401

Replace part, Adj., Wiring Harness, A/T Incl. diagnosis time 2005

37114

67

0

01

05

Use published labor operation time

 

 

 

 

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

 

 

© Copyright General Motors Corporation. All Rights Reserved.

[djkurious]

Hey thanks a lot! I will go ahead with the purchase of the ignition wiring harness as soon as I run these tests as you have listed. Once again, thanks!

[djkurious]

Where can a "SI" document be located on the web? Would the "SI" stand for service information? I was thinking maybe alldata.com has this information. Is this where I should go for this info?

 

Also, where is the transmission solenoid power supply circuit? I looked under the hood and could not find it? I also checked the fuse block in the engine compartment and the interior fuse block.

[GM-Tech]

Where can a "SI" document be located on the web?  Would the "SI" stand for service information? I was thinking maybe alldata.com has this information.  Is this where I should go for this info?

 

Yes, SI stands for GM's service information. Sometimes called eSI (electronic si). You can't find it on the web, at least not for free. It's very expensive but I understand they have something like a two day subscription for the average home user that just needs a one time use. It's still not cheap.

 

I wish I had a URL to give you but I don't. Seems to me ACDELCO was somehow involved in this SI subscription service.

 

Alldata may very well have the info you need. They're very good, so I hear, but just not quite as good as the manufacturer's information.

[GM-Tech]

You could try this... http://www.gmtechinfo.com/

 

That's for subscription information, not a free access site.