Check engine light

[blackf3504dr]

I pulled the codes and one has me baffled (easy to do), it is a CCA fault code.
Something about the cluster control assembly, I'm thinking it has something to do with the gauge cluster but am not sure... Any thoughts on what could be the problem? Two other codes were EGR valve and throttle position sensor, those I understand.....

[subford]

Need more info.
What are you working on?
If it is the 92" Holiday Rambler 1000 and is it on a 91 or 92 F53 chassis?
What were the code numbers?
What was the type of code number for each number, KOEO, CM or KOER?
It makes a difference as they mean a different error to the type of the number.

[blackf3504dr]

Hey sub',
It's a '91 F53. I redid the test, turns out it's a 632 code not the 532 I first thought.
632 is overdrive cancel switch (no switch action detected during engine run test). I've never taken it out of OD using the switch so it may or may not work.
The only reason I did the test was the check engine light came on shortly after replacing the fuel pump, I disconnected the chassis battery (over night) and the light was off for about a month then reappeared this past week. It seems to run fine but I am going to replace the EGR and check out the TPS.

[subford]

The 632 is an operator error during the KOER self-test. You are to push the OD button when told to do so during the test.

EGR codes for not opening after warm up on the road most of the time turn out to be bad vacuum lines or a bad EVR solenoid.
Sometimes you see a EGR valve stuck closed but that can be fixed by removing it and cleaning it most of the time. I am guessing that what the code was as you did not post the code number.

The TPS can be bad wiring or the sensor itself. You need to test it with a volt meter to see if it is your problem.

Sounds to me like you need to check the 5.0 VDC supply first as if it is off you will get the TPS and EGR codes. Check between VREF and SIG RTN on both the TPS and EVP sensor.

[blackf3504dr]

Thanks Bill, I haven't had a chance to check things out but suspect a vacuum line or dirty EGR too. I'll also check the voltage for the TPS while I'm at it.

[mpaton]

While you're in there, Id also be really interested to know which ECU your 1991 has. That would be identified by looking at the label on the ECU connector. That label has lots of numbers and letters on it, but the interesting ones are the 3 or 4 characters that are in a font size 3 or 4 times larger than all the other ones.

The ECU itself should be mounted vertically just in front of the steering column, right down at floor level, in front of the pedals. The connector will be on the bottom, right at the floor.

Those 3 or 4 digits are known as the "catch code" and are one way to identify the "calibration" of your engine and transmission. These are the settings that control the fuel injection settings, the ignition timing, the transmission shift points etc.

Bill and I have 1994 ECUs with the catch code TOE0. I had thought that a 91 would have generated 2 digit error codes, so I learned something already.

Remember also that these Ford OBD1 systems can have codes set that do not light the check engine light, so regular checks for codes are probably a good idea.

[blackf3504dr]

Quote:

Originally Posted by mpaton While you're in there, Id also be really interested to know which ECU your 1991 has. Bill and I have 1994 ECUs with the catch code TOE0. I had thought that a 91 would have generated 2 digit error codes, so I learned something already.

The book states that some '91 models use the three digit codes but I was expecting two digits. One thing that's constant is the inconsistencies. Sometimes I long for the days of carburetors and point ignitions ....

[subford]

Most if not all 1989 and newer Fords with the E4OD transmission had three digit codes.
Some that had a standard, C6 or AOD transmissions had two digit codes through 1994. All 1995 and later Ford F-series had three digit codes.
All of the 1989-1997 F53 Fords would have three digit codes with OBD-1 EEC-IV systems.
There was not a 1998 F53.
All of the 1998 Motorhomes had either the 1997 F53 with the 460 or the 1999 F53 with the V-10 engine.

[mpaton]

Quote:

Originally Posted by blackf3504dr The book states that some '91 models use the three digit codes but I was expecting two digits. One thing that's constant is the inconsistencies. Sometimes I long for the days of carburetors and point ignitions ....

My real interest is in understanding the internals of ALL the F53s with the 460. I do for my own, the TOE0 code. All others are similar, but with significant differences.

Occasionally if the price is right, I'll buy an ECU from a junkyard, just to get a look at the code (Ebay prices have gone too high for this). A couple of months ago I got one from a 1990 f350 with 460, and it has 2 digit codes, and less sophisticated controls than the later ones.

As yours was a 91 F53, I thought it might have 2 digit codes.

If you CAN locate that Catch Code for me, that would be useful for me. I'm hoping to develop a useful chip for the 460 engined F53, but I need to understand how many different ECU calibrations might be out there.

The upside for you is that with 3 digit codes, you almost certainly have the DCL feature, meaning you can connect a scanner to the ECU connector and read out live data as the engine is running.

However it may also mean that you don't have Closed Loop fuel control most of the time, which means the O2 sensor isn't allowed to do useful things, like compensate for ethanol fuels.

Do you have a catalytic converter on your 91? I would have guessed you did, but I don't trust that the F-series truck changes move in sync with the F53.

[blackf3504dr]

Yep, it has the cat.