[52B] SUPPLEMENTAL RESTRAINT SYSTEM (SRS) - - TROUBLESHOOTING - DIAGNOSTIC TROUBLE CODE PROCEDURES - Diagnosis code 27: Driver’s Seat Belt Pre-Tensioner (Squib) System Fault 2 (Open in the Squib Circuit) | PRINT PAGE / INDEX / PRIOR / NEXT

Diagnosis code 27: Driver’s Seat Belt Pre-Tensioner (Squib) System Fault 2 (Open in the Squib Circuit)
OPERATION The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU outputs an ignition signal. At this time, if the front air bag safing G-sensor is on, the pre-tensioner will deploy.
DIAGNOSIS CODE SET CONDITIONS This diagnosis code is set if there is abnormal resistance between the input terminals of the driver's seat belt pre-tensioner (squib).
PROBABLE CAUSES Improper connector contact Open circuit in the driver's seat belt pre-tensioner (squib) circuit Malfunction of the SRS-ECU
| DIAGNOSIS PROCEDURE
| STEP 1. Check the driver's seat belt pre-tensioner (Check whether the diagnosis code is reset). Disconnect the negative battery terminal.
| Disconnect driver's seat belt pre-tensioner connector D-29 <2400> or D-43 <2000>. Use a flat-tipped screwdriver to pull out the locking button at the harness side connector, and then disconnect the connector.
| Connect special tool dummy resistor (MB991865) to special tool resistor harness (MB991884). Connect special tool MB991884 to the D-29 <2400> or D-43 <2000> harness side connector. Connect the negative battery terminal. Erase diagnosis code memory, and then check the diagnosis code. Q: Is diagnosis code 27 set? YES: Go to Step 2. NO: Replace the driver's seat belt pre-tensioner (Refer to ). Then go to Step 3.
| STEP 2. Check the harness for open circuit between SRS-ECU connector C-114 (terminal No.29 and 30 <except 2400 (RH drive vehicles)>, No.27 and 28 <2400 (RH drive vehicles)>) and the driver's seat belt pre-tensioner D-29 <2400> or D-43 <2000> (terminal No.1 and 2).
| Disconnect SRS-ECU connector C-114 and driver's seat belt pre-tensioner connector D-29 <2400> or D-43 <2000>, and measure at the wiring harness side. For connector D-29 <2400> or D-43 <2000>, use a flat-tipped screwdriver to pull out the locking button at the harness side connector, and then disconnect the connector. Connect D-29 <2400> or D-43 <2000> harness side connector to special tool resistor harness (MB991884).
| CAUTION Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened. Check for continuity between the following terminals. <Except 2400 (RH drive vehicles)> SRS-ECU connector C-114 (terminal No.29) and special tool (terminal No.1) SRS-ECU connector C-114 (terminal No.30) and special tool (terminal No.2) <2400 (RH drive vehicles)> SRS-ECU connector C-114 (terminal No.27) and special tool (terminal No.2) SRS-ECU connector C-114 (terminal No.28) and special tool (terminal No.1) OK: Less than 2 Ω Q: Are the check results normal? YES: Erase the diagnosis code memory, and recheck if any diagnosis code sets. If diagnosis code 27 sets, replace the SRS-ECU (Refer to ). Then go to Step 3. NO: Repair harness wires between SRS-ECU connector C-114 and driver’s seat belt pre-tensioner connector D-29 <2400> or D-43 <2000>. Then go to Step 3.
| STEP 3. Check whether the diagnosis code is reset. Q: Is diagnosis code No.27 set? YES: Return to Step 1. NO: The procedure is complete (If no malfunctions are found in all steps, an intermittent malfunction is suspected). Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points .

[52B] SUPPLEMENTAL RESTRAINT SYSTEM (SRS) - - TROUBLESHOOTING - DIAGNOSTIC TROUBLE CODE PROCEDURES - Diagnosis code 27: Driver’s Seat Belt Pre-Tensioner (Squib) System Fault 2 (Open in the Squib Circuit) | PRINT PAGE / INDEX / PRIOR / NEXT

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