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AUTOMATIC TRANSMISSION DIAGNOSIS AUTOMATIC TRANSMISSION 23A-208 CIRCUIT OPERATION • A/T control relay (terminal 1) receives the battery positive voltage through a dedicated 20 amp • When the ignition switch is turned to the "ON" position, the A/T-ECU connector B-22 (terminal . DTC SET CONDITIONS Check Conditions • Voltage of battery: 9 volts or more. • Time after A/T-ECU turns on A/T control relay: 0.5 second or more. Judgement Criteria • A/T control relay output voltage: 7 volts or less. (0.1 second) • If (P1751) is set consecutively four times, the transmission is locked into 3rd gear as a fail-safe . OBD-II DRIVE CYCLE PATTERN Start the engine, and keep the vehicle stopped in "P" . TROUBLESHOOTING HINTS (THE MOST • Malfunction of the A/T control relay • Damaged harness or connector • Malfunction of the A/T-ECU Circuit drawings • Refer to circuit diagrams GROUP- • Refer to configuration diagrams GROUP- • Refer to component locations GROUP- DIAGNOSIS Required Special Tool: • MB991958: Diagnostic Tool (MUT-III Sub Assembly) • MB991824: V.C.I. • MB991827: MUT-III USB Cable • MB991910: MUT-III Main Harness A STEP 1. Using diagnostic tool MB991958, check data list CAUTION To prevent damage to diagnostic tool MB991958, always connector. (2) Turn the ignition switch to the "ON" position. • Item 8: A/T Control Relay Output Voltage. • The voltage should equal battery positive voltage. (4) Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the measured voltage equal battery positive voltage? YES : It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use − How to Cope with Intermittent Malfunction NO : Go to Step 2. 00DB076A MB991910 DATA LINK CONNECTOR MB991824 MB991827 |