Hey Y'all,


I am getting a code 54. I check across Pin G on the ACL and get .2 volts when it cycles on when you turn the key on.

I am getting 12 volts at pin A on the relay. I changed the relay out to a new one anyway.

This 383 swap is getting to me! I cannot shake out this code or the code 15.

Maybe my ECM is going.

Any help is greatl appreciated, I am ready to put a match to this thing.

RC :banghead:

 

Is that the correct voltage .2 (two tenths) or is that a typo?

If it's NOT a typo, then you should be getting 2 (two) volts; NOT .2 (two tenths).

There are several different things that can cause this low voltage code. Open circuits (there are a few that need to be checked), faulty fuel pump relay, faulty oil pressure switch, faulty ECM.

You'll need a test light and an ohm meter to check the circuits and connections.

The circuits to be checked (for the 86) are:

340; 120; 450; 465; ohm reading between terminals 'B' and 'C' on the fuel pump relay should 20 or more; faulty fuel pump ground, etc.

If you don't have a trouble-shooting manual and need the step by step checking procedures, let me know and I'll send them to you. Remember, the ones I have are for the 86, but I suspect they are much the same.

Jake

Jake


[Modified by JAKE, 4:39 PM 5/29/2004]

 

Here's something to get you started.

Test procedure:

Ignition "OFF" for 10 seconds
Ignition "ON" listen for in tank fuel pump
Pump should run for 2 seconds after ignition "ON"

If OKAY:

Clear Codes
Start engine and note 'SES' light
Light "ON"
Ground Diagnostic terminal and note code

If Code 54:
Back probe ECM terminal 'B2' with a test light to Ground
Ignition "OFF" for 10 seconds
Note Light within 2 seconds after ignition "ON"

Light "ON":

Faulty ECM terminal 'B2' or ECM

Light 'OFF':

Repair open CKT 120 to ECM terminal 'B2'

'B2' is the fuel pump signal at the ECM. It should have a RED wire, which is circuit 120.

The diagram shows that the RED wire (CKT 120) connects to the Oil Pressure Switch, 15 way I.P. connector, Front Body connector, the Fuel Pump Relay, the Rear Body Connector, Fuel Pump and the MAF Burn Off Relay and MAF Power Relay.

Busy little sucka isn't it.

Hope this helps.

Jake

 

Your Code 15 requires checking different circuits.

Coolant Sensor Signal High Voltage.

Here's the skinny on that one:

Ignition 'OFF' clear code
Diagnostic terminal NOT grounded
Start and warm engine and run for 1 minute or until SES light comes on
Ignition "ON" engine stopped
Ground Diagnostic terminal and note code

If Code 15:

Ignition 'OFF' Clear Code
Disconnect coolant temp sensor connector
Jumper harness terminal together
Start engine and run for minute or until SES light comes on
Ignition 'ON' engine stopped
Ground Diagnostic code and note code

If Code 15:

IF COOLANT TEMP IS FIXED BELOW -30C DISCONNECT SENSOR (which will give you a Code 15) {A Code 14 indicates the temp is fixed ABOVE 135C}

Ignition 'ON' engine stopped
Probe sensor coolant harness CKT 410 (YELLOW wire) with a volt meter to Ground
Should be 4-6 volts

If 4-6 volts:

Ign 'OFF'
Disconnect ECM C-D Connector
Check Circuit 452 for open circuit
If CKT 452 is not open, it is a faulty ECM connector or ECM

If volts are below 4 volts:

Ign 'OFF'
Disconnect C-D connector
Check circuit 410 for open circuit. If 410 is not open, it is a faulty ECM connector or ECM.

Both of your codes seems to lead to the possibility of a faulty ECM being the cause. Can you borrow one from a friend to see if it will cure BOTH codes?
That's what I did when I had an ignition timing problem several years ago.

Jake

 

I really appreciate the help to all.

I did change the oil pressure switch. Still getting the code 54. All in all I am getting 3 codes 42, 15, 54. I am using an Autoxray scanner to check them, which by the way seems to not be able read much else with any sense.

The car starts first turn but will not idle, timing is all over the place. Cooling fan will not come on either. Changed that relay and sensor and still nothing!
I have been manually turning it on with an alligator clip.

I am going to print out this and hit the garage! Gut feel it may be the ECM, scan errors and these codes and your feedback have me leaning that way!

What I wouldn't give for a carb engine.... at least then I would have half a chance!

Again thanks for the help. We'll hit the tests and see what we come up with.

RC

:cheers:

 

Jake,

It is .2 volts. I am using a Fluke meter, auto ranging. Even checked it myself on the battery to make sure it read 12.0. It did, went back to the ACL and got .2 again.

Argg!

 

I just glanced at the Code 42 trouble-shooting page and it has faulty ECM as it's core possible cause too.

So now all three codes have the ECM in the picture, Hmmmmmm!

Code 42 is exactly the one I was getting when I first bought my 86 and is the one I mentioned in a previous post that I borrowed an ECM from a friend and it solved my Code 42.

So I bought a remanufactured one from O'Reilly's for $99.00 - That was over 3 years ago and it's still going strong.

Jake

 

I'm not one to rush and buy replacement parts unless there's a reasonable certainty that the one installed is the cause, but, I agree, all these codes seem to be pointing at the ECM.

Code 42 has other possible causes listed too:

Faulty ignition module connection or the module itself
CKT 423 with an ohm reading higher than 500 ohms
Poor connection at 423
424 shorted to ground or open

Sounds more and more like the ECM though.

Jake

 

Jake,

I really appreciate the test list you gave me. I went out and performed all the test. I got the following feedback and want to make sure I am right in my thinking.

Code 54:

Pump runs with initial key on.
12 volts at relay
40ohms resistance between b/c on the pump
B2 circuit jumps to 12 volts, (light on) then off in less than a second at key on

If I understand correctly this points to a bad ECM or ECM connector


Code 15. Coolant sensor high

New sensor
5.04 volts across yellow wire
Circuit 452 at back of ECM is not open

This points to bad ECM as well?

I did not even chase the code 42. It seems to come and go. Gut feel, my ECM is bad, unless I am missing something.


Your post helped a lot. I owe you one!

RC


:cheers:

 

[SNIP]Jake, Code 54:Pump runs with initial key on.
12 volts at relay
40ohms resistance between b/c on the pump
B2 circuit jumps to 12 volts, (light on) then off in less than a second at key on

If I understand correctly this points to a bad ECM or ECM connector RC :cheers: [/SNIP]

If you cleared the Code 54 and it came back during the test, I'd say YES; it's the ECM terminal at B2 or the ECM itself.

The test says to note the light within 2 seconds after ignition "ON", so if it came on within 2 seconds it's the ECM termial B2 or the ECM.

If it did not come on at all within the 2 seconds, then it's an open circuit 120 that goes to the ECM terminal B2.

Jake