Code No.54: A/T Control Relay System
OPERATION
If a fail-safe operation is activated, the A/T control relay shuts off the power supply to the solenoid valve in accordance with the signal from the engine-A/T-ECU.
DIAGNOSIS CODE SET CONDITIONS
Code No.54 will be set if the A/T control voltage is less than 7 V after the ignition switch is turned on.
If code No.54 is set, the transmission will be held in 3rd gear.
PROBABLE CAUSES
  • Malfunction of A/T control relay
  • Damaged harness wires and connectors
  • Malfunction of the engine-A/T-ECU
DIAGNOSIS PROCEDURE
STEP 1. MUT-II/III data list
Item 54: Relay voltage (Refer to data list reference table
).
Q: Is the check result normal?
YES:  Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
NO:  Go to Step 2.
STEP 2. Check the A/T control relay connector
Refer to
.
Q: Is the check result normal?
YES:  Go to Step 3.
NO:  Replace the A/T control relay.
STEP 7. MUT-II/III data list
Item 54: Relay voltage (Refer to data list reference table
).
Q: Is the check result normal?
YES:  The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
NO:  Replace the engine-A/T-ECU.
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