Computer/Integrating System Diagnosis
DTC B1420
CIRCUIT DESCRIPTION
The body control module (BCM) monitors the battery voltage through the battery positive voltage circuit. If the BCM senses that battery voltage is outside of its normal range for 1 second, DTC B1420 will set.
DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC B1420 Device Voltage
CONDITIONS FOR RUNNING THE DTC
The voltage supplied to the BCM is in the range of 7-26 volts.
CONDITIONS FOR RUNNING THE DTC
The voltage supplied to the body control module is in the range of 7-26 volts.
CONDITIONS FOR SETTING THE DTC
- The BCM senses a battery voltage above or below the specified range of 9-16 volts.
- The above condition lasts for at least 1 second.
ACTION TAKEN WHEN THE DTC SETS
- The BCM will disable all its outputs when a high voltage condition is detected.
- The setting of this DTC inhibits the setting of other DTCs.
CONDITIONS FOR CLEARING THE DTC
- A current DTC clears when the malfunction is no longer present.
- A history DTC clears when the ignition has been cycled 100 times, without a repeat of the malfunction.
DIAGNOSTIC AIDS
- The following may cause an intermittent:
- A damaged terminal
- A backed out terminal
- A poor terminal tension
- A chafed wire
- A broken wire inside the insulation
- When diagnosing an intermittent short or an open, manipulate the wire harness while watching the test equipment for changes.
TEST
