No start. 01 eldorado

[rockfangd]

hi all.

I got a sinking feeling when I went to leave work tonight. My eldo would not start.

I have not had that happen in quite awhile so it surprised me.

I tried it several times and every time it did nothing. no click, or crank, or anything.

All accessories were fine

battery volts were 12.2v

It was not a theft issue. No security light or message.

Then weirdly It just fired right up like it never happened. Thank god, otherwise dont know where I would be.

I ran codes just to cover all bases

pulled 3 codes

PCM. U1152. history

SDM U1255 history

RFA U1064 history.

No clue what any of these mean. I recently printed out the compete code list for the modules but am not sure where it is.

I drive it every day. About 800-1000 miles a month. This is the first time It has done this.

I do know the battery terminals are clean and tight but I will recheck them. I replaced the ground cables to the battery a few months ago and always keep an eye on things.

I am sure someone here has some useful info.

Thanks all

[barczy01]

Start with the basics, check your battery and connections. I have replace the crappy GM battery bolts with a 3/8 bolts and nuts.

[rockfangd]

checked both. Both are good

[KHE]

Starter solenoid? Maybe the starter needs to be taken to a rebuilder and tested? They can pinpoint a bad solenoid and replace it much cheaper than the cost of chain-store junk starters.

[KevinW]

Park/Neutral switch contacts or adjustment? Intermittent starter enable relay continuity?

[barczy01]

Do you have a test light? Check and see if you have 12v on the purple wire near the power steering pump when in crank position on the ignition switch.

[rockfangd]

Lol if it will act up again.

And I did think of the NSS as a possibility.

Can someone decipher the codes I listed please. I cleared the pcm one, I want to see if it comes back.

Thanks all

[Cadillac Jim]

PCM
U1152 Loss Of ACM Serial Data Communication

SDM
U1255 Class 2 Communication Malfunction (Serial Data Line Malfunction)

RFA
U1064 Loss of Communications with DIM

I was about to mention the starter enable relay but the codes make it look like a short in the wiring that grounds the network wire. Do you need someone to look at the schematics to tell you where it might be?

[KHE]

Several years ago, I had a Buick Park Avenue and that decided it did not want to start and I traced the problem to corrosion on the contacts of the neutral safety switch/gear indicator switch on top of the transaxle. I unplugged it and the connector and switch contacts were literally green with corrosion. Once I cleaned it up, I never had the issue again.

[rockfangd]

PCM

U1152 Loss Of ACM Serial Data Communication

SDM

U1255 Class 2 Communication Malfunction (Serial Data Line Malfunction)

RFA

U1064 Loss of Communications with DIM

I was about to mention the starter enable relay but the codes make it look like a short in the wiring that grounds the network wire. Do you need someone to look at the schematics to tell you where it might be?

That would be wonderful. Could that be my no start cause?

I dont even know what ACM and DIM are.

[Cadillac Jim]

The ACM is the air conditioning module, the computer behind the A/C and heater buttons and the controller. The DIM is the Dash Integration Module.

The closest FSM that I have is the 2002 Eldorado, which is probably very much the same as 2000-2002 Eldorado. The network in the schematic has only two nodes that go to more than one module. They all go through splices S203 (node A in the schematics) and S324 (node B in the schematics. The best I can tell from your codes is that node B has a short.

Node A connects to the data link connector pin 2, the EBCM, the BCM, the SDM, and the Instrument Panel Cluster or IPC, which is probably the same thing as the DIM.

Node B connects to the ACM (labeled the "HVAC Control Processor in my schematic), the PCM, the radio (dash module, or IRC), the Vehicle Interface Unit (VIU), and the RFA (labeled "Remote Control Door Lock Receiver (RCDLR)" in my schematic), The Radio Interface module if you have the Bose system, and the CVRSS module if you have RSS.

The code U1152 looks like a short of node B. The U1255 looks like as short of node A but it's connected to node B through the MSM if you have memory seats, and then the radio. The U1064 could be either node, as the RFA connects to the DIM over node B through the ACM - but it also connects to the DIM through the BCM to node A.

So, it's not conclusive unless the schematic is inaccurate for your car, but a short of node B could explain the three codes.

Splice S203 (node A) is in the wiring harness 1.7 inches from the SDM breakout. Splice S324 (node B ) is in the wiring harness 2.5 inches from the radio breakout. I don't see either splice as the source of the short.

I would look at the connectors to the PCM, SDM (under the driver's seat), and RFA (behind the rear seat), the ACM (center of the console below the radio), and the DIM (behind the dash above the steering column). Looking at those locations, the one most likely inadvertently damaged one is the one under the driver's seat. Follow the PPL wire.

[Cadillac Jim]

Since the network codes didn't clearly flag a single point of a shorted line in the 2002 FSM, I looked in the 1997 FSM too. That one has a slightly different schematic. Interestingly enough, the same splice numbers, S203 and S324, are the main nodes for the network in the 1997 FSM. The layout of the drawings is entirely different but they may be in fact the same if you list what is connected to what.

This is all getting me to think that the codes you have aren't related to the starter problem, but are just old glitches that haven't had their codes time out yet. There are some things that will cause a no-click starting problem. Here's the 1997 FSM schematic of the starter circuit that I posted previously: