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
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STEP 1. M.U.T.-III data list
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Item 54: Relay voltage (Refer to
data list reference table ).
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Q.
Is the check result normal?
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Intermittent
malfunction (Refer to GROUP 00 - How to Cope with
Intermittent
Malfunction ).
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Go to Step
2.
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STEP 2. Check the A/T control relay
connector
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Refer to .
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Q.
Is the check result normal?
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Go to Step
3.
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Replace the
A/T control relay.
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STEP 3. Connector check: B-14X A/T control relay
connector
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![](../../../img/23/AC311979AC00ENG.png)
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Check for the contact with
terminals.
Q.
Is the check result normal?
Go to Step
4.
Repair
the defective connector.
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STEP 4. Measure the voltage at A/T control relay
connector
B-14X.
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![](../../../img/23/AC311979AC00ENG.png)
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Disconnect the A/T control
relay, and measure the voltage between terminal No.4
and earth at the relay box side. OK: System
voltage
Q.
Is the check result normal?
Go to Step
8.
Go to Step
5.
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STEP 5. Connector check: A-16 intermediate
connector
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![](../../../img/23/AC310403AJ00ENG.png)
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Check for the contact with
terminals.
Q.
Is the check result normal?
Go to Step
6.
Repair
the defective connector.
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STEP 6. Check the harness between A/T control
relay connector
B-14X terminal No.4 and battery.
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![](../../../img/23/AC311979AC00ENG.png)
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Check the power supply line for
short or open circuit.
Q.
Is the check result normal?
Go to Step
7.
Repair
the wiring harness.
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STEP 7. M.U.T.-III data list
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Item 54: Relay voltage (Refer to
data list reference table ).
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Q.
Is the check result normal?
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The trouble can be
an intermittent malfunction (Refer to GROUP 00 - How
to Cope with Intermittent Malfunction ).
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Replace the
engine-A/T-ECU.
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STEP 8. Measure the voltage at the A/T control
relay connector
B-14X.
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(1)Turn the ignition switch to the ON
position.
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![](../../../img/23/AC311979AC00ENG.png)
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(2)Disconnect the A/T control
relay, and measure the voltage between terminal No.3
and earth at the relay box side. OK: System
voltage
Q.
Is the check result normal?
Go to Step
11.
Go to Step
9.
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STEP 9. Connectors check: C-116 J/C (4), C-51 J/C
(13) <Vehicles
for Hong Kong and Singapore>, C-18 intermediate
connector, C-203 J/B connector
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![](../../../img/23/AC310615AT00ENG.png)
![](../../../img/23/AC310628AX00ENG.png)
![](../../../img/23/AC503532AB00ENG.png)
![](../../../img/23/AC310623AL00ENG.png)
![](../../../img/23/AC310618AK00ENG.png)
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Check for the contact with
terminals.
Q.
Is the check result normal?
Go to Step
10.
Repair
the defective connector.
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STEP 10. Check the wiring harness between A/T
control relay
connector B-14X terminal No.3 and junction block
connector C-203 terminal No.12.
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![](../../../img/23/AC311979AC00ENG.png)
![](../../../img/23/AC310623AL00ENG.png)
![](../../../img/23/AC310618AK00ENG.png)
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Check the power supply line for
short or open circuit.
Q.
Is the check result normal?
Go to Step
7.
Repair
the wiring harness.
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STEP 11. Measure the voltage at engine-A/T-ECU
connector
C-114.
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(1)Install the A/T control relay.
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(2)Turn the ignition switch to the ON
position.
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![](../../../img/23/AC311284AI00ENG.png)
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(3)Measure the voltage between
engine-A/T-ECU connector C-114 terminal No.123, No.124
and earth. OK: System voltage
Q.
Is the check result normal?
Go to Step
14.
Go to Step
12.
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STEP 12. Connector check: C-114 engine-A/T-ECU
connector
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![](../../../img/23/AC311284AI00ENG.png)
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Check for the contact with
terminals.
Q.
Is the check result normal?
Go to Step
13.
Repair
the defective connector.
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STEP 13. Check the harness between A/T control
relay connector
B-14X terminal No.1 and engine-A/T-ECU connector
C-114 terminal No.123, 124.
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![](../../../img/23/AC311979AC00ENG.png)
![](../../../img/23/AC311284AI00ENG.png)
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Check the power supply line for
short or open circuit.
Q.
Is the check result normal?
Go to Step
7.
Repair
the wiring harness.
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STEP 14. Connector check: C-114 engine-A/T-ECU
connector
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![](../../../img/23/AC311284AI00ENG.png)
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Check for the contact with
terminals.
Q.
Is the check result normal?
Go to Step
15.
Repair
the defective connector.
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STEP 15. Check the harness between A/T control
relay connector
B-14X terminal No.2 and engine-A/T-ECU connector
C-114 terminal No.127.
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![](../../../img/23/AC311979AC00ENG.png)
![](../../../img/23/AC311284AI00ENG.png)
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Check the output line for short or
open circuit.
Q.
Is the check result normal?
Go to Step
7.
Repair
the wiring harness.
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