Circuit Description
The body control module (BCM) monitors vehicle system voltage. Also, other modules monitor system voltage. The BCM sends a system voltage message to other modules that do not monitor system voltage via Class 2 message.
Conditions for Running the DTC
This DTC shall run only if the module has power, ground and the ignition is not in START mode. This DTC shall execute regardless of the battery voltage.
Conditions for Setting the DTC
| • | This DTC shall be set as current when the voltage falls below 9.0 volts for 1.2 seconds. |
| • | When the vehicle exits START the module shall delay checking the voltage for 2 seconds. |
Action Taken When the DTC Sets
| • | A message shall be sent out on the class 2 lines to notify all other modules of low battery voltage. |
| • | The modules disable the setting of U codes and other DTCs. |
Conditions for Clearing the DTC
| • | The DTC will clear current status when the voltage is less than 15.5 volts for 1.2 seconds. |
| • | A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present. |
| • | Use a scan tool. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Starting and Charging Schematics or Power Distribution Schematics in Wiring Systems Connector End View Reference: Master Electrical Component List in Wiring Systems | ||||
1 | Did you perform the Vehicle Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic Starting Point - Computer/Integrating Systems in Computer/Integrating Systems |
2 |
Does the scan tool indicate that DTC B1327 is current in more than 1 module? | -- | Go to Step 3 | Go to Step 6 |
3 |
Does the voltage measure greater than the specified value? | 9.4 V | Go to Step 11 | Go to Step 4 |
4 |
Does the voltage measure greater than the specified value? | 9.4 V | Go to Step 5 | |
5 | Measure the voltage between the battery positive voltage circuit of the BCM and a good ground. Does the voltage measure greater than the specified value? | 9.4 V | Go to Step 9 | Go to Step 8 |
6 |
Does the voltage measure greater than the specified value? | 9.4 V | Go to Step 10 | Go to Step 7 |
7 | Measure the voltage between the battery positive voltage circuit of the BCM or module setting DTC B1327 and a good ground. Does the voltage measure greater than the specified value? | 9.4 V | Go to Step 9 | Go to Step 8 |
8 | Test the batter positive voltage circuit of the BCM or module setting DTC B1327 for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 10 |
9 | Test the ground circuit of the BCM or module setting DTC B1327 for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 10 |
10 | Inspect for poor connections at the harness connector of the BCM or module setting DTC B1327. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 11 |
11 |
Important: Perform the setup procedure for the BCM or module setting DTC B1327, if necessary. Replace the BCM or module setting DTC B1327. Refer to Control Module References in Computer/ Integrating Systems. Did you complete the replacement? | -- | Go to Step 12 | -- |
12 |
Does the DTC reset? | -- | Go to Step 3 | System OK |
