Test 37A: Left Front Impact Sensor Internal 1, No Left Front Impact Sensor Communication

WARNING: This page is about a different car, the 2002 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Prior to performing any air bag system test, go to PRETEST INSPECTION & DIAGNOSTIC PROCEDURE under DIAGNOSTICS. Perform TEST VER-1: AIR BAG VERIFICATION TEST after all repairs unless otherwise directed.
Air Bag Control Module (ACM) harness connectors C1 and C2 are identical, except for wire colors and terminal usage. See WIRING DIAGRAMS .

Turn ignition switch to ON position. Using DRBIII, determine if LEFT FRONT IMPACT SENSOR INTERNAL 1 or NO LEFT FRONT IMPACT SENSOR COMMUNICATION are active or stored Diagnostic Trouble Codes (DTCs). If LEFT FRONT IMPACT SENSOR INTERNAL 1 or NO LEFT FRONT IMPACT SENSOR COMMUNICATION are active DTCs, go to next step. If LEFT FRONT IMPACT SENSOR INTERNAL 1 or NO LEFT FRONT IMPACT SENSOR COMMUNICATION are stored DTCs, go to TEST 1B: REPAIRING STORED CODES .
Disable air bag system. See DISABLING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Access and disconnect left front impact sensor. See FRONT IMPACT SENSOR under REMOVAL & INSTALLATION. Access Air Bag Control Module (ACM) and disconnect harness connector C2. See AIR BAG CONTROL MODULE (ACM) under REMOVAL & INSTALLATION. Turn ignition switch to ON position. Connect negative battery cable. Measure voltage in Light Blue wire between ground and harness side of left front impact sensor connector. See WIRING DIAGRAMS . If voltage is present, repair short to battery in Light Blue wire. If voltage is not present, go to next step.
Turn ignition switch to OFF position. Measure resistance in Light Blue wire between ground and harness side of left front impact sensor connector. Measure resistance in Dark Blue/Light Blue wire between ground and harness side of left front impact sensor connector. If resistance is less than 100 k/ohms in either circuit, repair short to ground in appropriate wire. If resistance is more than 100 k/ohms in both circuits, go to next step.
Turn ignition switch to OFF position. Measure resistance between Light Blue and Dark Blue/Light Blue wires on harness side of left front impact sensor connector. If resistance is less than 100 k/ohms, repair short between Light Blue and Dark Blue/Light Blue wires. If resistance is more than 100 k/ohms, go to next step.
Connect appropriate SRS load tool adapter to harness side of ACM connector C2. Measure resistance in Dark Blue/Light Blue wire between load tool adapter and harness side of left front impact sensor connector. If resistance is more than one ohm, repair open or high resistance in Dark Blue/Light Blue wire. If resistance is less than one ohm, go to next step.
Measure resistance in Light Blue wire between load tool adapter and harness side of left front impact sensor connector. If resistance is more than one ohm, repair open or high resistance in Light Blue wire. If resistance is less than one ohm, go to next step.
Replace left impact sensor and connect electrical connector. Remove all special tools and jumpers from air bag system. Reconnect all previously disconnect air bag components. Using DRBIII, erase all stored DTCs in all air bag control modules. Turn ignition switch to OFF position and wait 15 seconds. Turn ignition switch to ON position. Wait one minute. Using DRBIII, read active DTCs. If LEFT FRONT IMPACT SENSOR INTERNAL 1 or NO LEFT FRONT IMPACT SENSOR COMMUNICATION return as active DTCs, replace ACM. If LEFT FRONT IMPACT SENSOR INTERNAL 1 or NO LEFT FRONT IMPACT SENSOR COMMUNICATION DO NOT return as active DTCs, repair is complete.