P1772

DTC P1772 LOW COAST BRAKE SOLENOID VALVE

Description
Low coast brake solenoid valve is turned "ON" or "OFF" by the TCM in response to signals sent from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.

On Board Diagnosis Logic
^ This is an OBD-II self-diagnostic item.
^ Diagnostic trouble code "LC/B SOLENOID/CIRC" with CONSULT-II or P1772 without CONSULT-II is detected when TCM detects an improper voltage drop when it tries to operate the solenoid valve.

Possible Cause
^ Harness or connectors (The solenoid circuit is open or shorted.)
^ Low coast brake solenoid valve

DTC Confirmation Procedure

NOTE: If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch "OFF" and wait at least 10 seconds before conducting the next test.

After the repair. perform the following procedure to confirm the malfunction is eliminated.

WITH CONSULT-II
1. Turn ignition switch to "ON" position. (Do not start engine.)





2. Select "DATA MONITOR" mode for "A/T" with CONSULT-II.
3. Start engine.
4. Maintain the following conditions for at least 5 consecutive seconds.
Selector lever: "M" position
Gear position: "M1-1st" or "M2-2nd" gear (LC/B ON/OFF)
5. If DTC is detected, go to "Diagnostic Procedure".

WITH GST
Follow the procedure "With CONSULT-II".

AT-LC-B-01:

Wiring Diagram-AT-LC/B

Diagnostic Procedure
1. CHECK LOW COAST BRAKE SOLENOID VALVE CIRCUIT
1. Turn ignition switch to "OFF" position.
2. Disconnect A/T unit assembly harness connector at the transmission right side.








3. Check the resistance between terminal and ground.

OK or NG
OK >> GO TO 4.
NG >> GO TO 2.

2. CHECK TERMINAL CORD ASSEMBLY
1. Remove oil pan.
2. Disconnect A/T unit assembly harness connector and control valve assembly harness connector.








3. Check continuity between A/T unit assembly harness connector and control valve assembly harness connector.
4. If OK, check harness for short to ground and short to power.

OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.

3. CHECK VALVE RESISTANCE
Check valve resistance
^ Refer to "Component Inspection".

OK or NG
OK >> GO TO 4.
NG >> Replace the control valve assembly.

4. CHECK POWER SOURCE CIRCUIT
1. Turn ignition switch to "OFF" position.








2. Disconnect TCM connector.
3. Check continuity between A/T unit assembly harness connector and TCM connector.
4. If OK, check harness for short to ground and short to power.
5. Reinstall any part removed.

OK or NG
OK >> GO TO 5.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.

5. CHECK DTC
Perform "DTC Confirmation Procedure".

OK or NG
OK >> INSPECTION END
NG >> GO TO 6.

6. PERFORM TCM INSPECTION
1. Perform TCM input/output signal inspection.
2. If NG, recheck TCM pin terminals for damage or loose connection with harness connector.

OK or NG
OK >> INSPECTION END
NO >> Repair or replace damaged parts.

Component Inspection
INPUT CLUTCH SOLENOID VALVE
Resistance check
1. Turn ignition switch "OFF".
2. Remove oil pan.
3. Disconnect control valve assembly harness connector.








4. Check resistance between terminal and ground.
5. If NG, replace control valve assembly.

Operation check





^ Check solenoid valve by listening for its operating sound while applying battery voltage to the terminal 4 and ground.