Codes 21 & 22 Both Current - Steering Column Resistance Undetermined: Description

DERM injects a current of 75 milliamperes through steering column from FORCE HI output to FORCE LOW input. By monitoring voltage at SENSE HIGH input and SENSE LOW input, DERM calculates combined resistance of inflator module, SIR coil, harness wiring and connector terminal contact in steering column. Codes 22 and 21 will set if voltage at SENSE LOW input (terminal A6) is less than 5 volts during STEERING COLUMN RESISTANCE test. This occurs when FORCE HIGH output (terminal A4) is open and results in an undetermined steering column resistance.