[spacey1]

My 2001 Impala check engine light has come on with the code of P1887. My research indicates this is a electrical failure with the TCC solenoid. All of the trans solenoids have common power according to my schematic, so I am focusing on the ground(trigger) wire running to the PCM. I have some ideas on how to test this issue, but I would really like some feedback on how other have handled this issue.

Thanks.

 

[77Impala]

You can hook a DVM to the common hot for the transmission and the TCC ground wire and run the test leads into the car and watch (better yet have someone watch the display) and see if the computer triggers the TCC to activate. This will tell you if the PCM is calling for the TCC as it should, but you have to have the car moving past 20 MPH (I think, it may be lower) to activate it. If it has the 12+ power and the PCM grounds the TCC wire then most likely the TCC is bad.

Make sure the harness connections are tight and you might even reset the PCM and drive it for a few days and see if the MIL comes on again. I have seen that just reseting the PCM will eleminate many problems. But if the lamp relights and you get the same code then there is a problem.

 

[capricewiz]

The wire harness on the side of the trans is common for rubbing through either on the bottom of the Air filter box or on the bolt for the a/c receiver dryer. Check that harness for any pinched or rubbed through wires.

 

[spacey1]

I haven't tried the DVM with the car moving to see how it triggers, but I did strip the wire a little just past the transaxle coupling. With the car on, but not running, I grounded the wire and the TCC clicked every time. I am beginning to suspect the wiring harness itself or the connector. How difficult would it be to replace the entire wiring harness assembly?

 

[77Impala]

You will have to get it from a donnar car at a salvage yard. If you are good with soldering wireing then it wont be to hard. The question is how many attach points you will have to remove to get the harness out. I would pull enough to get past all of the bends and turns from the transmission upwards.

You may be able to fish the current harness up and just check it over and fix the problem(s) you find and reattach it back to the tranny. If you can this will save you some money.

I recently had a problem with my van where the neutral safety switch/reverse lamp harness was ripped from the tranny (not by me but a previous driver of the van) and could not find a donnar harness for it, so I simply repaired the harness and reattached it. Done it over a month ago and not one single problem.

 

[capricewiz]

Its easier to repair the wire if its broken. Its very rare that the connector itself is bad. Did you pull out the air box yet? If not pull it out and check the harness under the box.

 

[spacey1]

I did and couldn't find anything wrong with the wire or connectors so I took it to another shop for a second opinion this morning. They just called and said its the TCC Pressure switch and not electrical. Cost of repair is going to be $650.

 

[capricewiz]

if you get that switch replaced tell them to switch the pressure control solenoid while they're there.