Guys99A8

I have a basic OBD-II reader that shows no error codes. The car ran fine up until the time I had the driver’s side front well up on a jack swapping out the lower suspension bars and upper tie rod.

I started it once in this position then a second time work the steering. On the second time, it started to sputter and knock so I turned it off. Got it flat on the ground again and it won’t turn over. The starter is the only thing going off.

I put in a new fuel filter, fuel pump and sending unit, all of which work. I am getting gas to the fuel rails. The ECU units (2) are new also. I tried bypassing the fuel regulator to no avail.

I had previously switched out the spark plugs and tested the coils because of a misfire due to a bad ECU.

Is there another sensor or module which may have something to do with the ignition?

I’m new to this so please excuse any ignorance on my part. Any ideas?

TSHong

If you have fuel to the rails, have you verified that you do not have spark going to the spark plugs? Although you have fuel pressure at the rail, it does not mean the injectors are firing or at the right time. I would check to see if you have spark first?

Guys99A8

Thank you for your post. I finally broke down and bought the Ross-Tech software. I wish I would have done it years ago.

It's telling me the power relay for the ECU is bad. However, I can't tell which one it is or if I am even looking in the right spot, under the glove compartment. The Bentley’s diagram I have is not helpful.

I tried to attached some photos, the right size, but it won't let me do it. Can anyone tell me which one it is or where it is or if I am even looking in the right place?

Much thanks.

TSHong

The power relay for the ECU also powers the injectors as well. Sounds like you are on the right trail. The relay J271 is located in the relay box in the plenum chamber. The relay is #4 in the diagram.

audinutt

It looks like it's a 4 prong relay, if it is, you can check for voltage at terminal 30 (where terminal 30 on the relay plugs in).

If you have voltage there with the ignition on, you can check to see if you are getting voltage to the other side of the relay (terminal 87) or for a quick test jump 30 to 87, the car should run.

Guys99A8

Do you guy's happen to know where the e-plenum chamber is? From what I have been able to ascertain, it is outside the cab on the other side of the firewall, but I don't see it. There is a bracket behind the ECU but doesn’t have any modules, just wiring.

I have the part number 8D0 951 253 A location code 373 (I don’t know my J codes yet.)

I also do not find it inside on the passenger side.

Thanks

silverd2

The "E-Box" in the plenum chamber is where you found the ECU. The relay location (#4) should appear on the outlet after you unplug the relay.

That same relay part number and 373 location code is used in several locations for different systems. For wiring diagram purposes and actual location, #4 in the E-Box (plenum chamber)is what you're looking for. Should be a relay plate on the right (looking from front...toward the air intake, inside the E-Box) next to the TCM.

Guys99A8

Thanks for replying.

I would upload a picture, but it will not let me for some reason, the file is 2K kb in size.

Anyway, I still can't find it. I am looking where the ECU is, silver box on left, then you have fuses with one module in the middle to at the right, not the diagram I have been seeing, then on the cruise control module, then the transmission ECU. In back is a bracket with no modules, but has what appears to be a firing order to the wires coming from it. Would you happen to have a picture?

I don’t see anything else under the hood that holds modules. I'm stumped.

Thanks,

silverd2

Guy,
It should be the relay in the photo you emailed me. That same relay is shown in Bentley as the secondary air injection relay on my car ('01 40V), which it is. 2000 and up have the ECU relay in the passenger's foot well (central electric panel).

But on a '99 the same relay location (photo) is supposed to be the ECU power supply relay...99 and before don't have S.A.I.

The Bentley drawing isn't exactly a perfect match (has added fuse locations), but that is definitely where they indicate your relay to be located.

By the way, to upload photos, they have to have a URL address...so I put mine in PhotoBucket 1st, then right click to get "view image info", click on that and copy and paste that to the "insert image" box here above the dialog box.

Guys99A8

That’s the one. They changed the part number from 8D0 951 253 A location code no. 373 to 4H0 941 253 A location code 645 (FYI).

It tries to start now, but it is not getting enough or intermittent voltage so I am currently slow charging the battery at 2 amps rather than 6 amps as I don’t want to take the chance of screwing anything else up.

It gave me code for a possible open or short to ground fault code. Also a brake switch fault code which I think is old but I don’t want to clear it yet, and a new one regarding the air pollution sensor as I blew smoke trying to start it I’m sure.

I’m going to try and figure it out, I may have to ask for help again if I can’t.

I really appreciate yours, and everybody’s input. If it wasn’t for these forums, a lot of people would be screwed. I have discovered some issues in past dealings with one particular dealer that don’t jive.

Anyway, when I’m done I will articulate and post my findings so someone else may benefit.

Current fault codes:

18010 - Power Supply Terminal 30
P1602 - 35-10 - Voltage too Low - Intermittent
17925 - Power Supply Relay for ECU (J271 or J363)
P1517 - 35-10 - Electrical Malfunction – Intermittent

01274 - Air Flow Flap Positioning Motor (V71)
41-10 - Blocked or No Voltage - Intermittent
01592 - Air Quality Sensor (G238)
57-10 - Electric Circuit Failure – Intermittent

00776 - Level Control System Sensor; Left Front (G78)
31-00 - Open or Short to Ground

17087 - Brake Switch (F)
P0703 - 35-00 - Electrical Malfunction

Regards