DTC P0703 [L8, LF]

id0102b1809900

DTC P0703 | Brake switch input circuit problem
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DETECTION CONDITION | • The PCM monitors changes in input voltage from the brake switch No.1. If the input signal does not change while alternately accelerating and decelerating 8 times, the PCM determines that the brake switch No.1 circuit has a malfunction. Diagnostic support note • This is a continuous monitor (CCM). • The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM. • PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle. • FREEZE FRAME DATA (Mode 2/Mode 12) is available. • The DTC is stored in the PCM memory.
POSSIBLE CAUSE | Note • Inspect the brake switch with it installed to the brake pedal, otherwise the brake switch may not operate normally. If the brake switch is removed from the brake pedal, replace the brake switch with a new one. • Brake switch connector or terminals malfunction • Open circuit or short to ground in wiring harness between battery positive terminal and brake switch terminal B ― Short to ground in wiring harness between battery positive terminal and brake switch terminal B ― STOP 10 A fuse malfunction ― Open circuit in wiring harness between battery positive terminal and brake switch terminal B • Short to ground in wiring harness between brake switch terminal D and PCM terminal 1AB • PCM connector or terminals malfunction • Short to power supply in wiring harness between brake switch terminal D and PCM terminal 1AB • Open circuit in wiring harness between brake switch terminal D and PCM terminal 1AB • Brake switch No.1 malfunction • PCM malfunction

Diagnostic procedure

STEP | INSPECTION | ACTION
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1 | VERIFY FREEZE FRAME DATA (MODE 12) HAS BEEN RECORDED • Has the FREEZE FRAME DATA (Mode 12) been recorded? | Yes | Go to the next step.
No | Record the FREEZE FRAME DATA (Mode 12) on the repair order, then go to the next step.
2 | VERIFY RELATED SERVICE INFORMATION AVAILABILITY • Verify related Service Information availability. • Is any related Service Information available? | Yes | Perform repair or diagnosis according to the available Service Information. • If the vehicle is not repaired, go to the next step.
No | Go to the next step.
3 | INSPECT BRAKE SWITCH CONNECTOR AND TERMINALS • Turn the ignition switch off. • Disconnect the brake switch connector. • Inspect for poor connection (such as damaged/pulled-out pins, corrosion). • Is there any malfunction? | Yes | Repair or replace the connector or terminals, then go to Step 9.
No | Go to the next step.
4 | INSPECT BRAKE SWITCH NO.1 POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT OR SHORT TO GROUND • Brake switch connector is disconnected. • Turn the ignition switch to the ON position (engine off). • Measure the voltage between brake switch terminal B (wiring harness-side) and body ground. • Is the voltage B+? | Yes | Go to the next step.
No | Inspect the STOP 10 A fuse. • If the fuse is melt: ― Repair or replace the wiring harness for a possible short to ground. ― Replace the fuse. • If the fuse is deterioration: ― Replace the fuse. • If the fuse is normal: ― Repair or replace the wiring harness for a possible open circuit. Go to Step 9.
5 | INSPECT BRAKE SWITCH NO.1 SIGNAL CIRCUIT FOR SHORT TO GROUND • Brake switch connector is disconnected. • Turn the ignition switch off. • Inspect for continuity between brake switch terminal D (wiring harness-side) and body ground. • Is there continuity? | Yes | If the short to ground circuit could be detected: • Repair or replace the wiring harness for a possible short to ground. If the short to ground circuit could not be detected: • Replace the PCM (short to ground in PCM internal circuit). (See PCM REMOVAL/INSTALLATION [L8, LF].) Go to Step 9.
No | Go to the next step.
6 | INSPECT PCM CONNECTOR AND TERMINALS • Disconnect the PCM connector. • Inspect for poor connection (such as damaged/pulled-out pins, corrosion). • Is there any malfunction? | Yes | Repair or replace the connector or terminals, then go to Step 9.
No | Go to the next step.
7 | INSPECT BRAKE SWITCH NO.1 SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY • Brake switch and PCM connectors are disconnected. • Turn the ignition switch to the ON position (engine off). • Measure the voltage between brake switch terminal D (wiring harness-side) and body ground. • Is there any voltage? | Yes | Repair or replace the wiring harness for a possible short to power supply, then go to Step 9.
No | Go to the next step.
8 | INSPECT BRAKE SWITCH NO.1 SIGNAL CIRCUIT FOR OPEN CIRCUIT • Brake switch and PCM connectors are disconnected. • Turn the ignition switch off. • Inspect for continuity between brake switch terminal D (wiring harness-side) and PCM terminal 1AB (wiring harness-side). • Is there continuity? | Yes | Replace the brake switch, then go to the next step. (See BRAKE PEDAL REMOVAL/INSTALLATION.)
No | Repair or replace the wiring harness for a possible open circuit, then go to the next step.
9 | VERIFY DTC TROUBLESHOOTING COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the M-MDS. (See AFTER REPAIR PROCEDURE [L8, LF].) • Drive the vehicle 30 km/h {18.6 mph} or more. • Depress and release the brake pedal more than 8 times while driving vehicle. • Perform the Pending Trouble Code Access Procedure. (See ON-BOARD DIAGNOSTIC TEST [L8, LF].) • Is the PENDING CODE for this DTC present? | Yes | Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [L8, LF].)
No | Go to the next step.
10 | VERIFY AFTER REPAIR PROCEDURE • Perform the “AFTER REPAIR PROCEDURE”. (See AFTER REPAIR PROCEDURE [L8, LF].) • Are any DTCs present? | Yes | Go to the applicable DTC troubleshooting. (See DTC TABLE [L8, LF].)
No | DTC troubleshooting completed.