PINPOINT TEST G189021p1

Pinpoint Tests

CAUTION: When probing connectors to take measurements in the course of the pinpoint tests, use the adaptor kit, part number 3548-1358-00.

NOTE: When performing electrical voltage or resistance tests, always use a digital multimeter (DMM) accurate to 3 decimal places, and with an up-to-date calibration certificate. When testing resistance, always take the resistance of the DMM leads into account.

PINPOINT TEST G189021p1 : CHECK THE FORWARD ALERT SWITCH

G189021t1 : CHECK THE FORWARD ALERT SWITCH GROUND
1. Disconnect the forward alert switch electrical connector, FC43.
2. Measure the resistance between FC43, pin 09 (B) and GROUND.

- Is the resistance greater than 5 Ohms?

-> YES
REPAIR the high resistance circuit. TEST the system for normal operation.

-> NO
GO to Pinpoint Test G189021t2.

G189021t2 : CHECK THE FORWARD ALERT SWITCH TO ASCCM CIRCUIT FOR HIGH RESISTANCE
1. Disconnect the battery negative terminal.
2. Disconnect the ASCCM electrical connector, FH107.
3. Measure the resistance between FC43, pin 07 (GW) and FH107, pin 12 (GW).

- Is the resistance greater than 5 Ohms?

-> YES
REPAIR the high resistance circuit. TEST the system for normal operation.

-> NO
GO to Pinpoint Test G189021t3.

G189021t3 : CHECK THE FORWARD ALERT SWITCH TO ASCCM CIRCUIT FOR SHORT CIRCUIT TO GROUND
1. Measure the resistance between FC43, pin 07 (GW) and GROUND.

- Is the resistance less than 10,000 Ohms?

-> YES
REPAIR the short circuit. TEST the system for normal operation.

-> NO
GO to Pinpoint Test G189021t4.

G189021t4 : CHECK THE FORWARD ALERT SWITCH GROUND CIRCUIT FOR SHORT TO B+
1. Measure the voltage between FC43, pin 06 (B) and GROUND.

- Is the voltage greater than 3 volts?

-> YES
REPAIR the short circuit. This circuit includes the splice IPS 35. TEST the system for normal operation.

-> NO
INSTALL a new forward alert switch. CLEAR the DTC. TEST the system for normal operation. If the DTC is repeated, contact dealer technical support for advice on possible ECM failure.