Circuit Description
Battery positive voltage is supplied at all times to the seat adjuster switch and the memory seat module (MSM)/driver position module (DPM) through the same circuit. The MSM/DPM uses this battery voltage input to determine if battery positive voltage is applied to the seat adjuster switch.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B1420 Device Voltage
Conditions for Running the DTC
The MSM/DPM must be powered and cannot have B1327 Battery Voltage Low as an active DTC for this DTC to set.
Conditions for Setting the DTC
This DTC will set only when the MSM/DPM detects less than 3 volts from the circuit.
Action Taken When the DTC Sets
| • | Current and history codes are set. |
| • | The MSM/DPM ignores all memory recall commands. |
| • | All manual seat functions will operate. |
Conditions for Clearing the DTC
| • | The DTC will clear when the MSM/DPM detects that the voltage from the circuit is greater than 3 volts. |
| • | The MSM/DPM will clear the history DTC after 50 fault-free ignition cycles. |
Diagnostic Aids
The MSM is also known as the DPM for this vehicle.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Driver Seat Schematics Connector End View Reference: Power Seat Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 | Activate any one of the power seat adjuster switches. Does the seat move in the commanded direction? | Go to Step 3 | Go to Step 4 |
3 | Probe the battery positive voltage circuit of the memory seat module (MSM)/driver position module (DPM) connector C2 pin B11 with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 5 | Go to Step 6 |
4 | Test all of the power seat switch signal circuits between the seat adjuster switch and the MSM/DPM for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 7 |
5 | Inspect for poor connections at the harness connector of the MSM/DPM. 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 9 | Go to Step 8 |
6 | Repair the open in the battery positive voltage circuit of the MSM/DPM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | -- |
7 | Repair the short to ground or open in the battery positive voltage circuit of the MSM/DPM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | -- |
8 | Replace the MSM/DPM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 9 | -- |
9 |
Does the DTC reset? | Go to Step 2 | System OK |
