ECM going out?

[ExtremeSaleen]

I've been having some really weird issues lately, and I'm starting to suspect the computer. Was wondering if anyone has seen this before.

Symptoms are:
1. tach goes away and the mileage display goes to just dashes while the car is running. Shut if off and fire it back up and its working again.
2. speedometer will some times quit working. Same fix as above.
3. the car stalls a lot, but fires right back up
4. Get the check engine light a lot with a lot of weird codes, like the fuel sensor voltage, coils not working, EGR errors, DPFE not reading right, just all over the spectrum. (I clear them they don't come back, just a new one pops up).
5. Car is sometimes getting about 100 miles to a tank but that varies big time. Sometime 1/4 tank for 20 miles. Sometimes it seem completely normal.

If it is the ECM or sounds like it could be, how much does it cost to buy a new one, have replaced, etc.?

Thanks for any help or advise.

 

[LaserRed01GT]

If you can post all of the specific codes you have set, it would really help to diagnose your problem.

 

[Jakes]

When was the last time you had the battery and/or charging system checked out. Including bad or loose cable/wire connections. Low voltage will cause the ECM to go crazy and cause all sorts of problems.

 

[Rickey_Bobby]

I had the same problem a while ago....

Do you have a chip in the ECM?

The reason I ask is because the shop that originally tuned my car didnt tape the diablo chip in the computer. It would move around and reset the computer about 2 times a day. All kinds of wierd crap happened. Would die on the interstate, then fire right back up. All I had to do was tape the chip again.

I hope that is your problem as it is an easy fix. Hell, even if you done have a chip, check the connections to the ECM.

 

[ExtremeSaleen]

Thanks for the help. Yeah, the car is chipped, with two tunes. Started acting up after the last tune, so I thought maybe the system just got fried after so many time being retuned. I'll check under the side panel to see if anythings loose.

The code this morning was P-0460 : Fuel Tank Level Indicator Circuit Error. That's come up twice now. The other times where

P0350 Ignition Coil Primary/Secondary Circuit Malfunction
P0352 Ignition Coil B Primary/Secondary Circuit Malfunction
P0354 Ignition Coil D Primary/Secondary Circuit Malfunction
P1401 - Differential Pressure Feedback Electronic Sensor circuit High Voltage

Some others I can't remember now. I'll check out the battery and electrical. It is the original battery, maybe its time to upgrade to an optima.

 

[LaserRed01GT]

What's the PID reading for the differential pressure feedback sensor? If it is greater than 4.5 volts it will hard set a hard fault code. This can happen when the DPF sensor curcuit is shorted to ground or power, usually power.

Additionally the 3 coil related codes you got are also normally set when either the ignition circuit or the coild driver circuit are shorted to ground or vehicle power.

I would start by checking the PID values. On the FLI (fuel level indicator) circuit at a 1/4 tank the value should not be below .90 volts, at 3/4 tank the value should not be above 2.45 volts. If these values are within those parameters, then the FLI sensor and circuit are probably OK. If not, it may be a bad sensor or more likely a short to ground or power.

Do the same for the DPF EGR sensor. The PID should not be greater than 4.5 volts at key on engine off.

If all of these PID tests pass, then maybe there is a possibility that you have a damaged or chafed wire creating the short.