05 R/T disaster- where do I start??

[TV MAN]

Hi all. Well, like the title, where do I start? I think the list of what's wrong is longer than whats right. I bought the car a year ago, and have just recently started to repair. So, I will start with the worst. Not dependable. At all. It will start ok, run about 15 minutes, then stall. It always restarts, but I can time it and does it like clockwork. It doesn't matter if it's idling or running down the road. Codes - gee, where do I start?? Well, it did have a cam sensor code, so I replaced that. Then it threw a crank sensor code, so I replaced it. Now, those codes are gone, and it starts easier, but the stalling issue is still there. So, here are the codes I have pulled related: U0164, U0100, U110B and U0155 (this one is my fault cause I forgot to tighten the coolant cap after I serviced the cooling system and replaced water pump). It also has ABS codes, which shouldn't be related. Oh, when I do try to drive it, it bucks and bangs, like it is trying to stall and picks up or the trans isn't shifting right. It improves when it warms up and I keep the speed near 45mph. If I push it, the trans really bangs when it downshifts, but it will get up and go. Kinda wondering if there is some ground connection, wiring issue or something in common causing all of this.


The good? Well, the car sure is pretty sitting there and looks really fast. The inside is clean and in good shape. I didn't pay much for it, and the only honest thing the stealer told me was that it needed a tune-up. Any help would really be appreciated as to even where to start. I kinda suspect a fuel pump. But without a test port, I need to come up with some kind of Tee to connect my pressure tester.


Please help. The car isn't much good like it is.

Thanks in advance!

Tim

[jkelly16]

Sounds like you have wiring damage, bad connections or a bad PCM to me. If it's been sitting rodents may have chewed up some wiring harnesses.

[TV MAN]

I haven't really seen any rodent damage, but anything is possible. I am going to take a close look at the wiring from the PCM to the trans. Looks like most of the codes relate to communications problems on the trans. I may try bypassing the fuel pump relay and watch the pressure to see if the fuel pump is quitting.

I ran into this once on our 03 Cavalier. Like to never found it, but caught it one day with the pressure gauge on. When it acted up, the gauge looked like a windshield wiper. It had to be hot outside, run for 20 minutes and have less than 1/4 tank of fuel. Go figure.

[HemiLonestar]

U0164 lost communication with HVAC module - usually happens if the HVAC module is disconnected when power is put to the BUS (key turned to on or car started)
U0100 lost communication with ECM/PCM - this is where you need to check your wiring to it
U110B lost engine coolant - this is the "coolant code", not the one you referenced; this is a weird one because it's actually a TCM code and actually has nothing to do with the cooling system. Check connections to your TCM (under the dash, driver's side next to the amp). Does it shift properly? Does Autostick work correctly through ALL gears?

In case you doubt me, this is straight from the factory service manual:
U110B-LOST ENGINE COOLANT MESSAGE
Theory of Operation
The Transmission Control Module (TCM) receives information from the Engine, Anti-lock Brake System, and the Electronic Gear Shift control modules over the CAN C bus. The CAN C bus is a high speed communication bus that allows real time control capability between various controllers. Most messages are sent every 20 msec, this means critical information can be shared between multiple controllers almost instantaneously. The CAN C bus is a two wire bus with a CAN (+) and a CAN (-) circuit. To reduce the potential of radio and other electrical noise interference, the CAN Bus circuit wiring is manufactured using a twisted pair configuration within the electrical wiring harness.

• When Monitored: Continuously with the ignition on.
• Set Condition: The DTC will set if a valid CAN ID was not received in the required time from the ECM/PCM.

Possible Causes
TRANSMISSION CONTROL MODULE
if the code is active (cannot be erased), Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace and program the TCM.
U0155 lost communication with instrument cluster - could be a plug on the back of the cluster, could be the wiring that goes from the cluster to the FCM


You have some wiring to go through. Sometimes one good problem will cause others. I had a half bad TCM; auto shift was fine and partial autostick worked (but not full function). Had loss of comms code and the temp code. Dealership (worthless) told me it was fine. I showed the tech how it wasn't fine. He was dumbfounded. I had a spare known good TCM so I tried it; problem solved.

[TV MAN]

Thanks for the direction Lonestar. A new code showed up U1417 - no definition on my code tool. It also has the U140B and U1409 wheel sensor codes. ABS and ESP/BAS lights on. On the trans, NO, it doesn't shift correctly. Harsh is an understatement. Both upshifts and downshifts are harsh. It seems real sluggish going into 3rd (I believe). The auto-stick works, but still the shifts are harsh. I cant decide if it is slipping going into 3rd, or just sluggish. When it warms up, the problem seems to diminish, at least some, but cold, it is a bear.

It's obvious to me that some attempts have been made to find the problem, like a loose bolt on the PCM bracket and new sensors. I replaced both the left side wheel sensors with no change. I don't have codes anymore for the cam and crank sensors, so those must have been bad.

I really thought the coolant code was real since I did loose coolant due to a loose coolant tank cap. I thought I might have found the culprit in the ASD relay, so I swapped it with a other relay. It ran for almost 45 minutes idling, so I was getting in to make a test run. Didn't make it. Stalled. Did all kinds of weird things when trying to restart, like spark knock (like the timing was off), and kind of hit, but not enough to start (like its not getting fuel, or maybe flooding). So, still a no go. It finally did restart. I'm going to hold off messing with the fuel system, clean some grounds and check connections and wiring. Sounds like the TCM is goofy?

Also do you know the proper way to check the transmission fluid? I have a dipstick installed, just don't know if you check in neutral hot like most trans.

[HemiLonestar]

It's a wheel sensor code. Fluid check on the trans involves monitoring the trans temp and there is a factory chart for whereat level it should be at what temp. TCM could be goofy, but it wouldn't explain ALL your problems. You're getting constant BUS communication codes (all "U" codes are BUS comms codes); your car has deeper issues.

[TV MAN]

I started to check things tonite. I thought a good place to start was in the PCM area, so I pulled it and found it was a LKQ part. The connections looked clean, nothing obvious anyway, so I started checking grounds with the intention to clean, put on some silicone grease and reconnect. Well, I found something. On the rear of the engine near the trans dipstick tube is a ground connection going to the body, which had an additional ground wire cobbled on. That didn't bother me, but one of the 2 grounds coming from the injector/coil harness was burned! I dug somewhat deeper and it has burned inside the harness. I could feel other wires insulation damaged too. The good, if there is any, is that it doesn't look like anyone has been in this area attempting to repair or find a problem. So, it looks like I need to track down where this ground wire comes from, and 2, check the other wires that may be damaged against it. It goes towards the firewall. I don't have a manual or any kind of diagram, but it looks like I am going to have to pull the harness off the engine and try to follow it. If this ground goes through the firewall into the dash area, things could get real interesting. I hope this is not the case. This may very well explain the communication problem.

DSCN0804.JPG

[jkelly16]

Originally Posted by TV MAN

I started to check things tonite. I thought a good place to start was in the PCM area, so I pulled it and found it was a LKQ part. The connections looked clean, nothing obvious anyway, so I started checking grounds with the intention to clean, put on some silicone grease and reconnect. Well, I found something. On the rear of the engine near the trans dipstick tube is a ground connection going to the body, which had an additional ground wire cobbled on. That didn't bother me, but one of the 2 grounds coming from the injector/coil harness was burned! I dug somewhat deeper and it has burned inside the harness. I could feel other wires insulation damaged too. The good, if there is any, is that it doesn't look like anyone has been in this area attempting to repair or find a problem. So, it looks like I need to track down where this ground wire comes from, and 2, check the other wires that may be damaged against it. It goes towards the firewall. I don't have a manual or any kind of diagram, but it looks like I am going to have to pull the harness off the engine and try to follow it. If this ground goes through the firewall into the dash area, things could get real interesting. I hope this is not the case. This may very well explain the communication problem.

Attachment 1198

Not sure but this may have some info for you.

https://www.roswell-nm.gov/1112/Chil...Repair-Library

[TV MAN]

Thanks JKelly, I took a look. Interesting information, but in typical fashion, no wiring information that I could find. I would really like to find what that ground connects to or comes from. I will need to find and repair whatever made it burn up to begin with. I did locate an engine harness for $175 in case this one is too far gone.

[HemiLonestar]

Might be worth replacing the harness regardless