1988 Ford Thunderbird Hard Fault diagnostic code

  • 6 CYL
  • 2WD
  • 93,000 MILES
Hi I had my Ford put on a diagnostic machine at Autozone. I got a code number of 98--hard fault present. Could anyone explain what this code means and what needs to be done to fix this? Engine light is on and will not go off also.
If anyone can help I would appreciate it. When first started it has a bad miss and idles high, when you put into gear it smooths out but still idles fast.
Do you
have the same problem?
Sunday, February 8th, 2009 AT 9:19 PM

1 Reply

Hello .. thanks for the donation .. much appreciated

You need to get the PCM/ECA to pass self test with a code 11 .. code 98 means the system is not doing this .. this could be a fault on the ECA/PCM try these test's .. hope this helps .. let me know

CODE 98 - Vehicle did not pass KOEO SELF-TEST. Code 11 necessary to proceed with KOER test.

Test Procedure
Turn ignition switch to "OFF" position. Ensure all procedures of PREPARATION and EQUIPMENT HOOK-UP have been followed. Engine should be at normal operating temperature.
Ensure VOM or tester is connected properly. Turn ignition on. If Star Tester is being used latch center button in down position at this time.
The ECA will run through a test cycle, opening and closing various solenoids and switches. After the completion of the test cycle the codes will appear. Record all codes.
The first set of codes to appear are the KOEO SELF-TEST codes; they will be repeated twice, followed by the Separator Pulse signal and then the CONTINUOUS MEMORY codes. These codes will also be repeated twice.
A KOEO code 11 indicates the system has passed the self test. A code 11 must be present before continuing. Disregard any CONTINUOUS MEMORY codes at this time. Service KOEO codes (in the order they appear) and rerun KOEO test until a code 11 is displayed. See KEY ON ENGINE OFF (KOEO) CODE-TO-CIRCUIT TEST MENU .
Whenever a repair is made, repeat QUICK TEST . If no codes are displayed, repeat SELF-TEST to verify that other service codes are still present.

Analog Volt/Ohmmeter (VOM)
Turn ignition key to "OFF" position. Connect jumper wire from Self-Test Input (STI) pigtail to pin No. 2 (Signal Return) on SELF-TEST connector. Set VOM at 0-15V DC range and connect positive lead of VOM to positive battery terminal.
Connect negative VOM lead to pin No. 4 (STO) on SELF-TEST connector. Connect timing light, and go to KEY ON/ENGINE OFF (KOEO) SELF-TEST .
STAR Tester
Turn ignition key to "OFF" position. Connect color coded adapter cable leads to diagnostic tester. Connect adapter cable's 2 service connectors to vehicle's SELF-TEST connectors. Connect timing light, then go to KEY ON/ENGINE OFF (KOEO) SELF-TEST .
NOTE:Diagnostic tester hookup instructions apply to STAR tester only. If other than STAR tester is being used, follow diagnostic tester manufacturer's instructions.

Fig. 1: Equipment Hookup
Service codes are transmitted to Pin No. 4 (Self-Test Output) of SELF-TEST connector in the form of timed pulses. All service codes are 2 digit numbers which are generated one digit at a time. Codes are shown as voltage pulses (needle sweeps) on an analog Volt/Ohmmeter (VOM).
If a VOM is being used, pay careful attention to the length of the pauses in order to read the codes correctly. There will be a 2 second pause between each DIGIT in a code. There will be a 4 second pause between each CODE. The continuous memory codes are separated from the functional test service codes by a 6 second delay, a single 1/2 second sweep, and another 6 second delay. Always record the codes in the order received.
If a diagnostic tester is used, it will count the pulses and display them as a digital code. The STAR tester will add a zero (0) to single digit (Separator and Dynamic Response) codes. See CODE FORMAT DIAGRAMS in Fig. 2 .
If the "CHECK ENGINE" light is used, numeric service codes will be displayed at the light.
Separator Pulse
A single 1/2 second separator pulse is issued 6-9 seconds after last functional KOEO SELF-TEST code. Then 6-9 seconds after the single 1/2 second separator pulse, the continuous memory codes will be displayed.
Continuous Memory Codes
These codes are issued as a result of information stored during CONTINUOUS SELF-TEST. These codes are displayed during a KOEO SELF-TEST after the separator pulse code. These codes should be used for diagnosis, ONLY when KOEO and ENGINE RUNNING SELF-TESTS result in code 11 and all QUICK TEST steps have been successfully completed.
NOTE:If engine will not start, starts but stalls, idles rough or runs rough, go through KEY ON/ENGINE OFF (KOEO) SELF-TEST . If any of the above conditions are still present after a code 11 in the KOEO SELF-TEST, go to CIRCUIT TEST A1 for a no start condition. If engine stalls or runs rough, go to DIAGNOSIS BY SYMPTOM table.

Fig. 2: Code Format Diagrams



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Monday, February 9th, 2009 AT 7:55 PM

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