Test Notes

DTC B1945:
LH Primary Crash Sensor Not Mounted to Vehicle Properly or Ground Circuit Open

NORMAL OPERATION
The air bag diagnostic monitor measures the resistance between Pin C2-20, Circuit 620 (P/LB) and the reference ground at Pin C1-18 Circuit 57 (BK), Circuit 57 (BK). If the air bag diagnostic monitor measures a difference of more than 3.0 ohms between the ground at Pin C1-15, Circuit 57 (BK) and the ground at Pin C2-20, Circuit 620 (P/LB), the air bag diagnostic monitor will store in memory and flash lamp fault code 45 on the AIR BAG indicator. Should the difference in resistance between Pin C1-18 and C2-20, Circuit 620 (P/LB) be serviced or otherwise reduced to less than 3.0 ohms, the air bag diagnostic monitor will store DTC B1945 in memory.

NOTE: Circuit 620 (P/LB) is riveted to the side of the LH primary crash sensor case and the case of the sensor is grounded to the vehicle at its mounting point.

POSSIBLE CAUSES
A high resistance reading on Pin C2-20, Circuit 620 (P/LB) to ground can be caused by:

- a poor attachment of LH primary crash front air bag sensor and bracket due to loose mounting, dirt, or corrosion at its mounting location.

- an open or damaged wire in Circuit 620 (P/LB).

- an open wire or loose rivet inside LH primary crash front air bag sensor and bracket.

- a poor reference ground at Pins C2-10 and C1-18 of the air bag diagnostic monitor in Circuit 57 (BK).