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DTC 31









DTC 31: Low-Reverse Solenoid Valve System

CIRCUIT OPERATION
^ The A/T control relay supplies battery positive voltage to the solenoid valve assembly (terminals 9 and 10).
^ The solenoid valve closes when energized (on), and opens when not energized (off). The PCM energizes the solenoid valve based on input data from sensors such as the Throttle Position Sensor, Park/Neutral Position Switch, Stoplight Switch, Input Shaft Speed Sensor, Output Shaft Speed Sensor, and A/T Fluid Temperature Sensor.
^ The PCM provides the ground to energize the solenoid. The amount of time that the circuit is grounded is displayed on scan tool MB991502 in percent.
^ When the solenoid is energized or de-energized, fluid passes through the valve body and transaxle passages to apply and release components.

DTC SET CONDITIONS
If the resistance value for the low-reverse solenoid valve circuit is greater than 3.5 Ohms (open) or less than 2.6 Ohms (short) for 4 seconds, DTC 31 is set. The transaxle is locked into 3rd gear as a fail-safe measure.

TROUBLESHOOTING HINTS
(The most likely causes for this code to be set are:)
^ Malfunction of the low-reverse solenoid valve
^ Damaged harness or connector
^ Malfunction of the PCM

DIAGNOSIS

Required Special Tool:
^ MB991502: Scan Tool (MUT-II)

STEP 1. Using scan tool MB991502, check actuator test item 01: Low-Reverse Solenoid Valve.

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.





1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991502 to actuator test mode for item 01,
Low-Reverse Solenoid Valve.
^ An audible clicking or buzzing should be heard when the low-reverse solenoid valve is energized.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the solenoid valve operating properly?
YES: It can be assumed that this malfunction is intermittent.
NO: Go to Step 2.

STEP 2. Using scan tool MB991502, read the A/T diagnostic trouble code.





1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Check for A/T diagnostic trouble code.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC 54 set? (DTC 54 may be set along with multiple DTCs.)
YES: Refer to DTC 54: A/T Control Relay System.
NO: Go to Step 3.

STEP 3. Using scan tool MB991502, read the A/T diagnostic trouble code.





1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Check for A/T diagnostic trouble code.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC 36 set?
YES: Go to Step 8.
NO: Go to Step 4.

STEP 4. Measure the low-reverse solenoid valve resistance at A/T control solenoid valve assembly connector B-15.





1. Disconnect connector B-15 and measure at the solenoid valve side.





2. Measure the resistance between solenoid valve assembly connector B-15 terminals 6 and 10.
Resistance value: 2.7 - 3.4 Ohms [at 20°C (68°F)]
Q: Is the measured resistance 2.7 - 3.4 Ohms [at 20°C (68°F)]?
YES: Go to Step 6.
NO: Go to Step 5.

STEP 5. Measure the solenoid valve resistance at the low-reverse solenoid valve assembly inside the transaxle.





1. Disconnect connector B-15-5 and measure at the solenoid valve side.





2. Measure the resistance between low-reverse solenoid valve terminals 1 and 2.
Resistance value: 2.7 - 3.4 Ohms [at 20°C (68°F)]
Q: Is the measured resistance 2.7 - 3.4 Ohms [at 20°C (68°F)?
YES: Replace the harness wire between A/T control solenoid valve assembly connector B-15 and the solenoid valves.
NO: Replace the low-reverse solenoid valve.

STEP 6. Check A/T control solenoid valve assembly connector B-15 and PCM connector C-114 for loose, corroded or damaged terminals, or terminals pushed back in the connector.








Q: Are the connectors and terminals in good condition?
YES: Go to Step 7.
NO: Repair or replace the damaged components.

STEP 7. Check the harness for an open or short circuit to ground between A/T control solenoid valve assembly connector B-15 terminal 6 and PCM connector C-114 terminal 129.








Q: Is the harness wire in good condition?
YES: Replace the PCM.
NO: Repair or replace the harness wire.

STEP 8. Measure the supply voltage at A/T control solenoid valve assembly connector B-15.





1. Disconnect solenoid valve assembly harness connector B-15.
2. Turn the ignition switch to the "ON" position.





3. Measure the voltage between harness connector B-15 terminal 10 and ground.
^ The voltage should equal battery positive voltage.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage battery positive voltage?
YES: Go to Step 11.
NO: Go to Step 9.

STEP 9. Check A/T control relay connector B-11X in the engine component relay box and A/T control solenoid valve assembly connector B-15 for loose, corroded or damaged terminals, or terminals pushed back in the connector.








Q: Are the connectors and terminals in good condition?
YES: Go to Step 10.
NO: Repair or replace the damaged components.

STEP 10. Check the harness for an open circuit or short circuit to ground between A/T control relay connector B11X terminal 4 in the engine component relay box and A/T control solenoid valve assembly connector B-15 terminal 10.








Q: Is the harness wires in good condition?
YES: Go to Step 11.
NO: Repair or replace the harness wire.

STEP 11. Check A/T control solenoid valve assembly connector B-15 and PCM connector C-114 for loose, corroded or damaged terminals, or terminals pushed back in the connector.








Q: Are the connectors and terminals in good condition?
YES: Go to Step 12.
NO: Repair or replace the damaged components.

STEP 12. Check the harness for an open or short circuit to ground between A/T control solenoid valve assembly connector B-15 (terminals 6 and 7) and PCM connector C-114 (terminals 107 and 129).








Q: Are the harness wires in good condition?
YES: Go to Step 13.
NO: Repair or replace the harness wire.

STEP 13. Check the harness for an open or short circuit to ground between A/T control solenoid valve assembly connector B-15 (terminals 6, 7, and 10) and solenoid valve connectors B-15-4 and B-15-5.








Q: Is the harness wire in good condition?
YES: Replace the PCM.
NO: Replace the harness wire.

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