P0988
DTC P0988: Low-Reverse Brake Pressure Switch System
PRESSURE SWITCH SYSTEM CIRCUIT
Refer to P0846.
DESCRIPTIONS OF MONITOR METHODS
- During reverse driving, the switch OFF status continues for 2 seconds. (The detection is achieved twice during 1 driving cycle*1, and it continues for 2 driving cycles.)
*1: Indicates the series of driving cycle "ignition key OFF -> ON -> drive -> OFF." The "1 driving cycle," "2 driving cycle," and so on indicates how many cycles are required to detect a failure.
MONITOR EXECUTION
- Reverse gear driving
MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Not applicable
Sensor (The sensor below is determined to be normal)
- Not applicable
LOGIC FLOW CHARTS (Monitor Sequence)
DTC SET CONDITIONS
Check Conditions [Stuck-off]
- Transmission range switch position: R
- Gear position: reverse
- Time after shift changing finish: 2 seconds or more
Judgment Criteria [Stuck-off]
- Low-reverse brake pressure switch status: OFF (2 seconds x 2times)
Check Conditions [Stuck-on]
- Transmission range switch position: D
- Gear position: 1st, 2nd, 3rd, 4th, 5th, 6th
- Time after shift changing finish: 2 seconds or more
Judgment Criteria [Stuck-on]
- Low-reverse brake pressure switch status: ON (2 seconds x 2times)
OBD-II DRIVE CYCLE PATTERN
Reverse gear driving for 2 seconds or more
TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CODE TO BE SET ARE:)
- Malfunction of the low-reverse brake pressure switch system circuit
- Damaged harness or connector
- Malfunction of the TCM
- 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 Symptom Chart.
DIAGNOSIS
STEP 1. Check the DTC.
Q. Is the DTC other than the pressure switch set? (Is the code other than P0846, P0876, and P0988 set?)
YES Check and repair the relevant DTC system.
NO Go to Step 2.
STEP 2. Check the TCM terminal voltage.
[C-37 TCM connector (vehicle side, connected)]
Measure the voltage between C-37 terminal No. 43 and body ground.
- Low-reverse brake engaged: 0 V
- Other than above: Battery positive voltage
Q. Is the check result normal?
YES Go to Step 3.
NO Go to Step 7.
STEP 3. Check between the TCM connector and A/T control solenoid valve assembly.
Check for continuity between C-37 TCM connector and B-111 A/T control solenoid valve assembly connector.
NOTE:
Prior to the wiring harness inspection, check the intermediate connectors A-12 and repair that if necessary.
- Between C-37 terminal No. 43 and B-111 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?
YES Go to Step 4.
NO Repair or replace the failure section.
STEP 4. Check the TCM, A/T control solenoid valve assembly connector pin terminals, and the connection status.
Q. Is the check result normal?
YES Go to Step 5.
NO 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-111 A/T control solenoid valve assembly connector terminals and the low-reverse brake pressure switch connector terminals.
- Between B-111 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?
YES Go to Step 6.
NO Repair or replace the failure section.
STEP 6. Check the low-reverse brake pressure switch body ground.
Check for continuity between the low-reverse brake pressure switch body and ground.
- Between the low-reverse brake pressure switch body and body ground: Continuity exists.
Q. Is the check result normal?
YES Replace the valve body assembly, and then go to Step 8.
NO Repair or replace the failure section.
STEP 7. Check the TCM, A/T control solenoid valve assembly connector pin terminals, and the connection status.
Q. Is the check result normal?
YES Go to Step 9.
NO Repair or replace the failure section.
STEP 8. Erase the DTC code, and drive the vehicle for a while.
Check that the normal code is displayed.
Q. Is the check result normal?
YES The procedure is complete.
NO Replace the TCM.
STEP 9. Erase the DTC code, and drive the vehicle for a while.
Check that the normal code is displayed.
Q. Is the check result normal?
YES The procedure is complete.
NO Return to START.