Test TC: Step 17
17) Service Code 91, 92, 93, 94, 98 And 99 Circuit Identification These service codes indicate that the appropriate On/Off solenoid is out of Self-Test range. This may cause harsh, early or late shifting. Reading should be 9-14.5 volts when ON and less than 1.0 volt when OFF. Code 98 indicates Electronic Pressure Control (EPC) solenoid may have a faulty driver in the ECA. Code 99 indicates a faulty EPC circuit which may cause harsh shifting and clutch wear. Possible causes for these codes are: solenoid resistance is out of limits, harness circuit is open or grounded, faulty ECA.
| Solenoid | Abbreviation | Test Pin No. | Code |
|---|---|---|---|
| Shift Solenoid No. 1 | SS1 | 52 | 91 |
| Shift Solenoid No. 2 | SS2 | 19 | 92 |
| Coast Clutch Solenoid | CCS | 55 | 93 |
| Converter Clutch Solenoid | CCC | 53 | 94 |
| Elect. Pressure Control | EPC | 38 | 98/99 |
If any of the listed codes are present, go to step 15) for 7.3L diesel vehicles or next step for all others. If codes are not present, go to KOEO Self-Test procedures.