Code 98 w.t.f.?

You're in over my head - I read the codes in Probst - but I don't have a clue what it's trying to tell you. If the engine was off when you pulled the code it's "Electronic Pressure Control (EPC) driver failure in processor"; if the engine was running it's "Hard fault is present - FMEM (Failure Mode Effects Management). I have no idea what any of that is referring to. So now that I'm subscribed maybe Senor Richker can tell us what it's all about.

BaBysARM said:

JRichter

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LOL, Richter is a Judge in German. i have always meant to ask him if that is the etymology of his name. i think "The Judge" would be a cool CT for Mr. Richker.


my foggy memory is telling me that 98 is from non-competion of the KOEO test - no code 11 established. i though the other part had something to do with the tranny. my thoughts are worth what you paid for them though - very foggy.

good luck.

Appropriate given his technical prowess and even-headed demeanor.

Code 98 does not indicate a 6 cylinder computer. Here's what I found and where I got the info...

See http://www.troublecodes.net/Ford/ for more info

Code 98 - Did not pass KOEO yet (Get 11 in KOEO first)

Or see http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

98 (r): Hard fault present. The PCM is running in FMEM (Failure Effects Management Mode), so something is royally screwed up that the KOEO test should have told you about. Rerun KOEO and fix whatever you find there.

No other codes other than 98 and the computeris getting good power, the computer is probably bad. Find a buddy to let you put your computer in his car and re-run the tests. That way, if something is messed up in your wiring or sensors, the computer will not fail in a good car and cause you to replace a good computer -

Bad power or low voltage to the computer could cause this problem.

Time to get out the digital voltmeter (DVM) & go hunting...

Diagram courtsey of Tmoss & Stand&2birds.


Pop the passenger side kick panel off and remove the plastic cover over the computer wiring. You will need the diagram above along with a safety pin to probe the wiring from the back side of the connector. Use the computer's case shield grond for a ground for the DVM. Check pins 37 & 57 (switched computer power) for battery voltage with the engine running. The difference between the voltage on pins 37 & 57 and the postive post of the battery should be less than .5 volt.

Check pin 19 for voltage with the engine off - you should see battery voltage. The difference between the voltage on pin 19 and the postive post of the battery should be less than .5 volt.

Check pins 40 & 60 (computer power ground) you should see less than .5 volt. More than this means the computer's power ground is bad. The computer has its own dedicated power ground that comes off the ground pigtail on the battery ground wire. It uses a barrel type quick disconnect connector inline with the battery ground pigtail. Due to it's proximity to the battery, it may become corroded by acid fumes from the battery.

The engine mounted sensors have a common separate ground. This includes the TPS, ACT, EGR, & BAP/MAP. These sensors share a black/white ground wire that connects to computer pin 46. With the power off, measure the resistance between pin 46 and the negative post on the batery. You should see less than .5 ohm.

The secondary power ground is between the back of the intake manifold and the driver's side firewall. It is often missing or loose. It supplies ground for the alternator and other electrical accessories such as the gauges. Any car that has a 3G alternator needs a 4 gauge ground wire running from the block to the chassis ground where the battery pigtail ground connects.

The O2 sensor heaters have their own ground (HEGO ground) coming from the computer. This is different and separate from the O2 sensor ground. It comes out of the fuel injector harness near the EGR valve.