Circuit Description
The SBI data line is used to communicate information between the door modules. Each module connected to the SBI is assigned its own recognition code (address). This code is used to identify which modules are communicating. Modules communicate with each other by periodically sending State of Health (SOH) messages. When the ignition switch is in RUN, each module communicating on the SBI sends a State of Health (SOH) message every two seconds to ensure that the system is operating properly. When the RFDM stops communicating on the SBI, for example if the RFDM loses power or ground, the SOH message it normally sends on the SBI every two seconds disappears. The LFDM which expects to receive that SOH message, detects its absence and sets DTC U1161current.
Conditions for Setting the DTC
| • | The LFDM does not receive a State of Health (SOH) message back from the RFDM. |
| • | This DTC only sets if DTC B1982, B1983, U1300 or U1301 is not current in module memory. |
Action Taken When the DTC Sets
| • | DTC U1161 is stored in module memory. |
| • | The LFDM uses the default values for the initialization data. |
| • | This DTC does not cause a driver warning message to appear. |
Conditions for Clearing the DTC
| • | This DTC clears (status changes from current to history) under any of the following conditions: |
| - | The LFDM detects a State of Health Message from the RFDM. |
| - | On each ignition cycle. |
| • | A history DTC clears after 50 consecutive ignition cycles if the conditions for setting the DTC are no longer present. |
| • | Current and history DTCs may be cleared using a scan tool or using the ON-Board System Diagnostic feature. |
Diagnostic Aids
| • | DTC module U1161 does not normally represent a failure within the module. |
| • | If the DTC is a history DTC, the problem may be intermittent. |
| • | A grounded CKT 2076 will set following DTCs U1161, U1162, U1163, and U1170. |
| • | An open or a high resistance wire between the LFDM and S303 will set DTCs U1161, U1162, U1163. |
Test Description
The numbers below refer to the step numbers on the diagnostic table:
-
This step inspects for other related DTC that are set.
-
This step inspects for related DTCs that are set.
-
This step inspects the PASS MDL fuse.
-
This steps tests for battery voltage in CKT 740 at the RFDM.
-
This steps tests for ground in CKT 451 at the RFDM.
-
This steps tests for continuity of the simple bus interface from the RFDM to the LFDM in CKT 2076.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Power Door Diagnostic System Check performed? | -- | Go to Step 2 | |
Are DTCs U1162 and U1163 and U1170 also set? | -- | Go to Step 3 | Go to Step 7 | |
3 | Repair the short to ground in CKT 2076. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 4 | |
4 |
Important: Do not reconnect a component once you disconnected the component. Leaving the LH front door module (LFDM) connected, disconnect the other door modules or the LH front power window switch one at a time while monitoring the DTC status. Do the DTCs change from current to history status when a component is disconnected? | -- | Go to Step 5 | Go to Step 6 |
5 |
Did you complete the repair? | -- | -- | |
6 | Replace the LFDM. Refer to Door Control Module Replacement . Did you complete the repair? | -- | -- | |
Are DTCs U1162 and U1163 also set? | -- | Go to Step 8 | Go to Step 9 | |
8 | Repair any open or high resistance in CKT 740 from the LFDM to S303. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 6 | |
Remove and test the PASS MDL fuse. Is the fuse open? | -- | Go to Step 10 | Go to Step 11 | |
10 | Repair a short to ground in CKT 740. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Diagnostic Aids | |
Does the voltage measure within the specified range? | 10-15 V | Go to Step 13 | Go to Step 12 | |
12 | Repair the open or the high resistance in CKT 740. Refer to Wiring Repairs in Wiring Systems. | -- | -- | |
Using a DMM, measure resistance between RFDM harness connector C1 terminal 4 and ground. Does the resistance measure within the specified range? | 0-5 ohms | Go to Step 15 | Go to Step 14 | |
14 | Repair the open or the high resistance in CKT 451. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
Does the resistance measure within the specified range? | 0-5 ohms | Go to Step 17 | Go to Step 16 | |
16 | Repair the open or the high resistance in CKT 2076. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
17 | Replace the RH front door module (RFDM). Refer to Door Control Module Replacement . Is the replacement complete? | -- | -- |
