AT-16 AUTOMATIC TRANSMISSION — Troubleshooting (Diagnosis System) TROUBLESHOOTING FLOW-CHART HINT: • If diagnostic code Nos. 42, 61, 62 or 63 are indicated out, the indicator light will begin to blink immediately to warn the driver. However, an impact or shock may cause the linking to stop; but the code will still be retained in the ECT ECU memory until canceled out. • There is no warning for diagnostic code No. 64. • In the event of a simultaneous malfunction of both No. 1 and No. 2 speed sensors, no diagnostic code will appear and the fail-safe system will not function. However, when driving in the D range, the transmission will not up-shift from first gear, regardless of the vehicle speed. Diagnostic code 42 (No. 1 speed sensor circuitry) Check continuity between ECT ECU connector SP₁ terminal and body ground. (See page AT-29) | NG OK Substitute another ECT ECU. Check No. 1 speed sensor. (See page AT-31) | NG → Repair or replace No. 1 speed sensor. OK Check wiring between ECT ECU and combination meter. Diagnostic code 61 (No. 2 speed sensor circuitry) Check continuity between ECT ECU connector SP₁ terminal and body ground. (See page BR-46) | NG OK Substitute another ECT ECU. (w/ A.B.S.) | (w/o A.B.S.) Check A.B.S. circuit. (See page BR-46) | Check No. 2 speed sensor. (See page AT-31) | NG → Repair or replace No. 2 speed sensor. OK Check wiring between ECT ECU and No. 2 speed sensor.