DTC P1727 / P1728
Precautions: Precautions for Diagnosing Trouble · Precautions for Disassembly and Reassembly · Precautions for Transmission / Transaxle · General safety (00)
DTC Detecting Condition and Trouble Area
| DTC detecting condition | Trouble area |
|---|---|
|
P1727: Reverse Lamp Control Circuit Low Back up light relay drive circuit is open or shorted to ground. (1 D/C detection logic) |
•Back up light relay and/or its circuit
•TCM |
|
P1728: Reverse Lamp Control Circuit High Back up light relay drive circuit is shorted to power supply. (1 D/C detection logic) |
Circuit Diagram
| [A]: | TCM connector (View: [a]) | 1. | TCM | 7. | IG1 relay |
| [B]: | Ignition switch model | 2. | CPU | 8. | To battery |
| [C]: | Keyless push start model | 3. | Back up light relay | 9. | To keyless start control module |
| A1: | Back up light relay power supply circuit (coil side) | 4. | Back up light | 10. | Ignition switch |
| B1: | Back up light relay drive circuit | 5. | J/B | ||
| C1: | Back up light relay power supply circuit (switch side) | 6. | “BACK” fuse |
DTC Confirmation Procedure
NOTE:
Check that the following condition is met in this “DTC Confirmation Procedure”.
•DTC U0073 or U0100 is not detected.
1)Set ignition “ON”.
2)Shift select lever to R range and wait for 10 sec.
DTC Troubleshooting
| Step | Action | Yes | No |
|---|---|---|---|
| 1 |
Was “A/T Control System Check” performed?
|
Go to Step 2.
|
Go to A/T Control System Check.
|
| 2 |
Back up light relay power supply circuit (coil side) check
1)With ignition “OFF”, remove back up light relay.
2)Check for proper terminal connection to back up light relay connector.
3)If connection is OK, set ignition “ON”.
4)Check that voltage between “A1” and ground is battery voltage.
Is check result OK?
|
Go to Step 3.
|
Repair or replace defective wire harness.
|
| 3 |
Back up light relay check
1)Check back up light relay.
Is check result OK?
|
Go to Step 4.
|
Replace back up light relay.
|
| 4 |
Back up light relay drive circuit check
1)Disconnect TCM connector.
2)Check for proper terminal connection to TCM connector.
3)If connections are OK, check the following points.
•Resistance of “B1” circuit: less than 1 Ω
•Resistance between “B1” circuit and ground: infinity •Resistance between “B1” circuit terminal and other terminal at TCM connector: infinity •Voltage of “B1” circuit: approx. 0 V (When ignition is “ON”) Is check result OK?
|
Substitute a known-good TCM and recheck DTC.
|
Repair or replace defective wire harness.
|