Circuit Description
The LH Seat Control Module (SCM) has two main power feeds (high and low), and one main ground. The low power feed (battery 1) is used to provide power for the SCM logic and internal driver operation. The high power feed (battery 2) is used to provide power for systems that draw higher amounts of current (motors, lights etc.). For most functions, the SCM will operate properly when vehicle system voltage is between 9.0-16.0 volts. The SCM also monitors the voltage level at battery 1 and battery 2 circuits and can determine if the voltage level received is out of range. If the voltage level is out of range in either circuit , then a malfunction is present and a DTC will set.
Conditions for Setting the DTC
| • | The SCM detects battery 1 voltage range under 8.5 volts or over 16.3 volts. |
| • | Condition must be present for 2 seconds. |
Action Taken When the DTC Sets
| • | Stores a history DTC B0851 in the SCM memory. |
| • | This DTC can only be set as a history code even if the malfunction is current. |
| • | No driver warning message will be displayed for this DTC. |
Conditions for Clearing the DTC
| • | The SCM detects battery 1 voltage range between 8.5-16.3 volts for longer than 2 seconds. |
| • | Use the IPC clearing DTCs feature. |
| • | Using a scan tool. |
Diagnostic Aids
| • | If the DTC does not reset after the code is cleared, then the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur. Refer to Intermittents and Poor Connections |
| • | The following conditions may also cause an intermittent malfunction: |
| - | There is an intermittent open or short to ground in CKTs 2140 or 1740. |
| - | The battery voltage is not within range (8.5-16.3 volts). |
| - | A charging system malfunction. |
| • | Using a scan tool, select SCM Data display and monitor battery 1 voltage while test driving the vehicle and operating different devices (windows, door locks, power mirrors, etc.). This can determine if battery 1 voltage is affected by these devices and can help duplicate the malfunction. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Is the voltage within specified range? | 10.0-14.0V | ||
2 | Replace the Seat Control Module (SCM). Is the repair completed? | Recheck the System Operation | ||
3 |
Is the voltage within specified range? | 10.0-14.0V | ||
4 | Repair the open in the CKT 1740, between the connector C301 terminal E and the Seat Control Module (SCM) connector C1 terminal 3. Is the repair complete? | Recheck the System Operation | ||
5 |
Is the voltage within the specifed range? | 10.0-14.0V | ||
6 | Repair the open in the CKT 2140, between the connector C301 terminal E and the instrument panel electrical center connector C1 terminal C12. Is the repair complete? | Recheck the System Operation | ||
7 | Replace the instrument panel electrical center. Is the repair completed? | Recheck the System Operation |
