Part 3 of 4

METRO-DTC 24

STEERING COLUMN CIRCUIT VOLTAGE TOO LOW








Circuit Description:
DTC 24 is set when the voltage at the "Sense Low" input, terminal "A6", is within a specific range of "36 VLR" output voltage for 500 milliseconds during the "Continuous Monitoring Tests" performed by the DERM. The "Continuous Monitoring Tests" are performed by the DERM after the initial "Turn-ON Tests" are completed and are performed every 100 milliseconds while "Ignition 1" voltage is present at the DERM. The "Continuous Monitoring Tests" check the continuity of the deployment loop from the "36 VLR" output of the DERM through the arming sensor, inflator module and the discriminating sensors to ground. DTC 24 will set if the arming sensor resistance is too high or open, a discriminating sensor is shorted or resistance is too low, the "Force High," "Sense Low" or "Force Low" circuit is shorted to ground or system voltage, or the "Sense High" circuit is shorted to ground.
Test Conditions:
Tested every 100 milliseconds during the "Continuous Monitoring Tests."
Failure Conditions:
DTC 24 will set if the voltage at the "Sense Low" input, terminal "A6", is within a specif-ic range of "36 VLR" output voltage for 500 milliseconds.
Action Taken:
The DERM illuminates the "INFL REST" indicator.
Conditions to Clear: DTC 24 will clear if the voltage at the "Sense Low" input, terminal "A6", is within a specific range of "36 VLR" output voltage for 500 milliseconds.
Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.

14. This test checks for a short to B + in CKT 347.
15. This test checks for a short to B + in CKT 348.
16. This test checks for a short to B + in the "Force Low" CKT 688.
17. This test checks for a short to B + in the "Force High" CKT 714.
18. This test checks for a short to B + in the "Sense Low" CKT 752.
19. This test checks for an open in CKT 347A.