Circuit Description
The LH Front Door Module (LFDM) Diagnostic Check is an organized approach to identify problems associated with the Door Control System. This check is the starting point for all module complaints, and directs you to the next logical step in diagnosing the complaint. The module is a very reliable component and is not likely the cause of the malfunction. Most system complaints are linked to faulty wiring and connectors, and occasionally to components. Understanding the computer system and using the tables correctly will reduce diagnostic time and prevent unnecessary parts replacement.
Diagnostic Aids
| • | The following conditions may result in an intermittent operation of the module with no DTC stored: |
| - | Any condition which results in the interruption of power to the module |
| - | Out of range battery or ignition voltage |
Specification
Normal module operating voltage: 9.0-16.0 V
| - | A loose or damaged ground(s) |
| - | An open or shorted serial data line |
| • | An intermittent failure in the electronic system may be very difficult to detect and to accurately diagnose. The module tests for different malfunctions under different vehicle conditions. For this reason, a thorough test drive is often needed in order to repeat a malfunction. If the system malfunction is not repeated during the test drive, a good description of the complaint may be very useful in locating an intermittent malfunction. Faulty electrical connections or wiring causes most intermittent problems. When an intermittent condition is suspected, check the suspected circuits for the following conditions: |
| - | Poor mating of connector halves or backed out terminals |
| - | Improperly formed or damaged terminals |
| - | Wire chafing |
| - | Poor wire to terminal connections |
| - | Dirty or corroded terminals |
| - | Damage to connector bodies |
| • | Use the J 35616 whenever a diagnostic procedure requests probing or checking a terminal. Using this adapter will ensure that no damage to the terminal will occur, and will give an idea of whether contact tension is sufficient. |
| • | If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur. Perform a thorough inspection of all related wiring and connectors pertaining to the history DTC stored. |
| • | Exit all scan tool tests before cycling the ignition OFF to ON unless the scan tool instructions direct otherwise. Follow the operating instructions in the scan tool operator's manual. Failure to follow these instruction may set DTCs, cause vehicle system malfunctions, set false DTCs, or cause scan tool malfunctions. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Does the scan tool communicate with the LFDM? | -- | ||
2 | Attempt to establish communications with the other modules connected to the same serial data line (PCM, EBTCM, IPC, etc.). Does the scan tool communicate with the other modules? | -- | Go to the applicable Loss of Class 2 Serial Data Communication DTC in Body Control Systems | Go to Data Link Connector (DLC) |
3 | Select Display LFDM DTC function with the scan tool.Are any current DTCs stored? | -- | ||
4 | Are U1016, U1064, U1065, U1066, U1255, U1300 and/or U1301 Loss of Class 2 Serial Data Communication DTCs set | -- | Go to the applicable Loss of Class 2 Serial Data Communication DTC in Body Control Systems | Go to Door Control System DTC List |
5 | Is the customer complaint with the Power Mirrors? | -- | Go to Outside Mirrors System Check | |
6 | Is the customer complaint with the Power Door Locks? | -- | Go to Power Locks Diagnostic System Check | Go to Power Windows Diagnostic System Check |
