Diagnostic Tool Display Shows "Missing" For One or More System

The Diagnostic Tool's Display Shows "MISSING" For One Or More Systems.

Fault symptoms
The word "MISSING" flashes on the diagnostic tool's display for one or more Systems.

Condition
The following condition is applicable:
- Ignition switch in ON position

Diagnostic help
If all systems (except the DICE) are missing, check the I bus for an open circuit at the DICE or a short circuit anywhere at all in the wiring. Use the NIGHT PANEL button to distinguish between the two types of fault.

If one or more systems are missing, check whether the control modules are awake and allow diagnostics communication. If this is the case, study the wiring diagram to find out exactly where in the bus network the fault is located on the basis of which system or systems are missing.

The potential between bus+ and ground and between bus- and ground should be 2-3 V. All control modules put out this voltage.

The diagnostic tool's main menu "All systems/Read configuration shows a list of the systems fitted to the car as original equipment.

On the right of each system, "OK" will be shown if the system is communicating correctly or "MISSING" if the system is missing from the bus.

If a new control module is installed in the car, it will automatically be included on the list.

If a control module for the CD changer or radio, for instance, is removed from the car, the list can be reset to zero with the command under "All systems/Read configuration/Clear."

Checking the wiring harness
Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short-circuits in the leads. Observe the multimeter, test lamp or diagnostic tool during the test.

Diagnostic procedure

1 Checking whether the DICE can communicate with a control module connected to a bus

Does MISSING flash on the diagnostic tool's display for all systems except the DICE?
YES
- Go to point 2.
NO
- Go to point 5.

2 Checking the I bus
- Turn the ignition switch to ON.





- Press NIGHT PANEL on the SID.





- The main instrument unit's odometer display should go out.





Function OK?
YES
- Go to point 3.
NO
- Go to point 4.

3 Diagnostic procedure for the DICE bus wiring harness
- The cause of the fault is an open circuit between pin 14 of the DICE and crimp connection J72 (green lead) or between pin 5 of the DICE and crimp connection J73 (white lead).
- The diagnostic instrument shows OK when communication starts.
- Clear the diagnostic trouble codes in all systems.





- Carry out a function test.

Function OK?
YES
- The steps taken to rectify the fault were correct.
NO
- See "Before changing a control module."

4 Diagnostic procedure for the bus wiring harness
- The cause of the fault is a short circuit in the I bus+ or I bus- at any point in the connected wiring harness or internally in a connected control module.
- Turn the ignition switch to ON.





- Select: All systems/Bus configuration in the diagnostic tool's main menu.





- The diagnostic instrument shows OK when communication starts.
- If necessary, disconnect one control module at a time to trace a possibly faulty one.
- The potential between bus+ and ground and between bus- and ground should be 2-3 V. All control modules put out this voltage.
- Rectify the fault.
- Clear the diagnostic trouble codes in all systems.





- Carry out a function test.

Function OK?
YES
- The steps taken to rectify the fault were correct.
NO
- See "Before changing a control module."

5 Checking that the control modules allow diagnostics communication
- See the table describing how to determine whether a missing control module allows diagnostics communication.

Do all "MISSING" systems allow diagnostics communication?
YES
- Go to point 6.
NO
- Go to point 7.

6 Diagnostic procedure for the bus wiring harness
- The cause of the fault is an open circuit on bus+ or bus- (if only the Trionic or TCM and Trionic are missing, the fault could also be due to a short circuit in the P bus).
- Turn the ignition switch to ON.





- Select: All systems/Bus configuration in the diagnostic tool's main menu.





- The diagnostic instrument shows OK when communication starts.
- If necessary, disconnect one control module at a time to trace a possibly faulty one.
- The potential between bus+ and ground and between bus- and ground should be 2-3 V. All control modules put out this voltage.
- Rectify the fault.
- Clear the diagnostic trouble codes in all systems.





- Carry out a function test.

Function OK?
YES
- The steps taken to rectify the fault were correct.
NO
- See "Before changing a control module." Before Changing A Control Module

7 Diagnostic procedure for the control module's current supply
- See the table for which fuses must be intact and which pins must have a current supply (+30 and +15 circuits) and ground for missing control modules to allow diagnostic communication.
- Turn the ignition switch to ON. Control Module Connections





- Select: All systems/Bus configuration in the diagnostic tool's main menu.





- The diagnostic instrument shows OK when communication starts.
- If necessary, disconnect one control module at a time to trace a possibly faulty one.
- The potential between bus+ and ground and between bus- and ground should be 2-3 V. All control modules put out this voltage.
- Rectify the fault.
- Clear the diagnostic trouble codes in all systems.





- Carry out a function test.

Function OK?
YES
- The steps taken to rectify the fault were correct.
NO
- See "Before changing a control module." Before Changing A Control Module