DTC 54 (P1751): A/T Control Relay System

CIRCUIT OPERATION
A/T control relay (terminal 1) receives battery positive voltage through a junction block.
The PCM (terminal 50) applies voltage to energize the A/T control relay (terminal 4). With the A/T control relay energized, system voltage is applied to the PCM (terminals 77 and 89).
DESCRIPTIONS OF MONITOR METHODS
If relay output voltage is below specified value, PCM judges that A/T control relay has a failure.
MONITOR EXECUTION
Continuous
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)

Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
• DTC 41 (P0731): 1st gear incorrect ratio
• DTC 42 (P0732): 2nd gear incorrect ratio
• DTC 43 (P0733): 3rd gear incorrect ratio
• DTC 44 (P0734): 4th gear incorrect ratio
• DTC 46 (P0736): Reverse gear incorrect ratio
• DTC 36 (P0743): Torque converter clutch solenoid malfunction
• DTC 31 (P0753): Low-reverse solenoid malfunction
• DTC 32 (P0758): Underdrive solenoid malfunction
• DTC 33 (P0763): Second solenoid malfunction
• DTC 34 (P0768): Overdrive solenoid malfunction

Sensor (The sensor below is determined to be normal)
• Torque converter clutch solenoid
• Low-reverse solenoid
• Underdrive solenoid
• Second solenoid
• Overdrive solenoid
LOGIC FLOW CHARTS (Monitor Sequence)
DTC SET CONDITIONS

Check Conditions
Voltage of battery: 9 volts or more.
Time after PCM 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 DTC 54 (P1751) is set consecutively four times, the transmission is locked into 3rd gear as a fail-safe measure, and the "N" range light flashes once per second.
OBD-II DRIVE CYCLE PATTERN
Start the engine, and keep the vehicle stopped in P range for 5 seconds.
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:
Malfunction of the A/T control relay
Damaged harness, connector
Malfunction of the PCM