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Test Notes

NORMAL OPERATION

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.

The air bag diagnostic monitor measures the resistance between Pin C277-20, Circuit 620 (P/LB) and the reference ground at Pin C276-18, Circuit 57 (BK). If the air bag diagnostic monitor measures a difference of more than 3.0 ohms between the ground at Pin C276-18, Circuit 57 (BK) and the ground at Pin C277-20, Circuit 620 (P/LB), the air bag diagnostic monitor will store in memory and flash Lamp Fault Code (LFC) 45 on the AIR BAG indicator. Should the difference in resistance between Pin C276-18 and C277-20, Circuit 620 (P/LB) be serviced or otherwise reduced to less than 3.0 ohms, the air bag diagnostic monitor will store Diagnostic Trouble Code (DTC) B1945 in memory.

POSSIBLE CAUSES
A high resistance reading on Pin C277-20, 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 C277-10 and C276-18 of the air bag diagnostic monitor in Circuit 57 (BK).