Code No. P0988: Low-Reverse Brake Pressure Switch System

PRESSURE SWITCH SYSTEM CIRCUIT

DIAGNOSIS CODE SET CONDITIONS

note

^*1 Indicates the series of driving cycle in the order of "ignition key OFF, ON, drive and OFF." The "1 driving cycle," "2 driving cycle," and so on indicates how many cycles are required to detect a failure.

PROBABLE CAUSES

Malfunction of the low-reverse brake pressure switch system circuit
Damaged harness or connector
Malfunction of the A/T-ECU
Malfunction of the low-reverse brake pressure switch system (valve body assembly)
Malfunction of the valve body assembly, abnormal hydraulic circuit valve.

caution

For the incomplete gear shifting and slippage, first refer to the SYMPTOM CHART

DIAGNOSIS PROCEDURE

STEP 1. Check the diagnosis code.

Q. Is the diagnosis code other than the pressure switch set? (Is the code other than P0841, P0846, P0871, P0876, and P0988 set?)

	Check and repair the relevant diagnosis code system.

	Go to Step 2.

STEP 2. Check the A/T-ECU terminal voltage.

[C-137 A/T-ECU connector (vehicle side, connected)]

Measure the voltage between C-137 terminal No. 43 and body earth.

Low-reverse brake engaged: 0 V
Other than above: System voltage

Q. Is the check result normal?

	Go to Step 3.

	Go to Step 7.

STEP 3. Check between the A/T-ECU connector and A/T control solenoid valve assembly.

Check for continuity between C-137 A/T-ECU connector and B-131 A/T control solenoid valve assembly connector.

Between C-137 terminal No. 43 and B-131 terminal No. 7: Continuity exists.

When the continuity check result is OK, check that the wiring harness is not shorted to the body and other wiring harness.

Q. Is the check result normal?

	Go to Step 4.

	Repair or replace the failure section.

STEP 4. Check the A/T-ECU, A/T control solenoid valve assembly connector pin terminals, and the connection status.

Q. Is the check result normal?

	Go to Step 5.

	Repair or replace the failure section.

STEP 5. Check between the A/T control solenoid valve assembly connector and low-reverse brake pressure switch.

Check for continuity between the B-131 A/T control solenoid valve assembly connector terminals and the low-reverse brake pressure switch connector terminals.

Between B-131 terminal No. 7 and low-reverse brake pressure switch: Continuity exists.

When the continuity check result is OK, check that the wiring harness is not shorted to the body and other wiring harness.

Q. Is the check result normal?

	Go to Step 6.

	Repair or replace the failure section.

STEP 6. Check the low-reverse brake pressure switch body earth.

Check for continuity between the low-reverse brake pressure switch body and earth.

Between the low-reverse brake pressure switch body and body earth: Continuity exists.

Q. Is the check result normal?

	Replace the valve body assembly, and then go to Step 8.

	Repair or replace the failure section.

STEP 7. Check the A/T-ECU, A/T control solenoid valve assembly connector pin terminals, and the connection status.

Q. Is the check result normal?

	Go to Step 9.

	Repair or replace the failure section.

STEP 8. Erase the diagnosis code, and drive the vehicle for a while.

Check that the normal code is displayed.

Q. Is the check result normal?

	The procedure is complete.

	Replace the A/T-ECU.

STEP 9. Erase the diagnosis code, and drive the vehicle for a while.

Check that the normal code is displayed.

Q. Is the check result normal?

	The procedure is complete.

	Return to START.