B1551
This document has been updated per Mitsubishi TSB# 09-52b-002DTC B1551: SRS warning light circuit malfunction (light does not illuminate).
CIRCUIT OPERATION
- Power for the SRS warning light is supplied from the ignition switch (IG1) circuit.
- The SRS warning light illuminates when the ignition switch is turned to the "ON" position and goes out after approximately seven seconds if there is not a malfunction in the SRS system.
DTC SET CONDITIONS
This diagnostic trouble code will be set if the SRS warning light driving circuit is short to ground.
TROUBLESHOOTING HINTS
- Damaged wiring harnesses of connectors
- Malfunction of the SRS-ECU
- Malfunction of the combination meter
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: MUT-III USB Cable
- MB991911: MUT-III Main Harness B
STEP 1. Check the combination meter connector C-01.
Q: Is the connector correctly engaged?
YES: Go to Step 2.
NO: Engage the connector correctly. Then go to Step 7.
STEP 2. Voltage measurement at combination meter connector C-01.
1. Disconnect the combination meter connector C-01.
2. Connect the negative battery terminal.
3. Turn the ignition switch to the "ON" position.
4. Measure the voltage between C-01 harness side connector terminal 9 and body ground.
OK: Approximately 12 volt
Q: Is the check result satisfactory?
YES: Go to Step 4.
NO: Go to Step 3.
STEP 3. Check the harness for open circuit between ignition switch and combination meter connector C-01 (terminal No.9).
NOTE: Prior to the wiring harness inspection, check junction block connector C-21, C-211 and C-214, and repair if necessary.
Q: Is the check result satisfactory?
YES: there is an intermittant malfunction such as poor engaged connector(s) or open circuit (Refer to How to Cope with Intermittent Malfunction).
NO: Repair the harness wires between ignition switch and the combination meter connector C-01 (terminal No.9) Then go to Step 7.
STEP 4. Check SRS-ECU connector C-28.
Q: Is the connector correctly engaged?
YES: Go to Step 5.
NO: Engage the connector correctly. Then go to Step 7.
STEP 5. Check the harness for short circuit between the combination meter connector C-02 (terminal No. 36) and SRS-ECU connector C-28 (terminal No. 26).
Q: Is the check result normal?
YES: Go to Step 6.
NO: Repair the harness wires between the combination meter connector C-02 (terminal No. 36 and SRS-ECU connector C-28 (terminal No. 26). Then go to Step 7.
STEP 6. Check the SRS warning light.
1. Disconnect the negative battery terminal.
2. Disconnected the SRS-ECU connector C-28.
3. Connect the negative battery terminal.
4. Turn the ignition switch to the "ON" position.
Q: Does the SRS warning light illuminate?
YES: Go to Step 7.
NO: Replace the combination meter (Refer to Combination Meter Assembly). Go to Step 7.
STEP 7. Recheck for diagnostic trouble code.
Check again if the DTC is set.
1. Erase the DTC.
2. Turn the ignition switch to the "ON" position.
3. Check if the DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC B1551 set?
YES: Replace the SRS-ECU.
NO: There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to How to Cope with Intermittant Malfunction).
CIRCUIT OPERATION
- Power for the SRS warning light is supplied from the ignition switch (IG1) circuit.
- The SRS warning light illuminates when the ignition switch is turned to the "ON" position and goes out after approximately seven seconds if there is not a malfunction in the SRS system.
DTC SET CONDITIONS
- This diagnosis code will be set if an open circuit has occurred in the wiring harness between the SRS warning light and the SRS-ECU.
TROUBLESHOOTING HINTS
- Damaged wiring harnesses or connectors
- Malfunction of the SRS-ECU
- Malfunction of the combination meter
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: MUT-III USB Cable
- MB991911: MUT-III Main Harness B
STEP 1. Check the harness between SRS-ECU connector C-28 (terminal No. 26) and the combination meter connector C-02 (terminal No. 36).
- Check the SRS warning light output lines for open circuit.
Q: Is the check result satisfactory?
YES: Go to Step 2.
NO: Repair the harness wires, Then go to Step 3.
STEP 2. Check the SRS warning Light.
1. Disconnect the negative battery terminal.
2. Disconnected the SRS-ECU connector C-28, and measure at the warning harness side.
3. Connect the negative battery terminal.
4. Turn the ignition switch to the "ON" position.
CAUTION: Do not insert a probe into the terminal from its front side directly, as the connector contact pressure may be weakened.
5. Check that SRS warning light turn "ON" when SRS-ECU connector C-28 is disconnected. Check that the same above connector is grounded.
Q: Is the check result satisfactory?
YES: Go to Step 3.
NO: Replace the combination meter (Refer to Combination Meter Assembly).
STEP 3. Recheck for diagnostic trouble code.
Check again if the DTC is set.
1. Erase the DTC.
2. Turn the ignition switch to the "ON" position.
3. Check if the DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC B1551 set?
YES: Replace the SRS-ECU.
NO: There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to How to Cope with Intermittant Malfunction).