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NOTE:
The lead is routed via the 10-pole plug connection on the heater/ A/C unit.
Short to B+
1. Pull oft plug II on the display and operator control unit.
2. Pull oft plug C on the heater / A/C control unit.
3. Check lead from plug II pin 15 to plug C 12 for short to B+.
Signal disturbance
Check wiring harness for short with other leads.
Test point 2
Data lead, navigation unit-PCM
Open circuit/short to ground
Short to B+ Signal disturbance
Fault code 21
Open circuit/short to ground
1. Pull off plug II on the display and operator control unit.
2. Pull off plug on the navigation unit.
3. Check lead from navigation unit plug pin 7 to plug II pin 17 for continuity and short to ground.
Short to B+
1. Pull off plug II on the display and operator control unit.
2. Pull off plug on the navigation unit.
3. Check lead from navigation unit plug pin 7 to plug II pin 17 for short to B+.
Signal disturbance
Check lead from navigation unit plug pin 7 to plug II pin 17 for short with other leads.
Test point 3
Data lead, PCM-navigation unit
Short to ground
Short to B+
Fault code 22
Short to ground
1. Pull off plug II on the display and operator control unit.
2. Pull off plug on the navigation unit.
3. Check lead from navigation unit plug pin 5 to plug II pin 4 for short to ground.
Short to B+
1. Pull off plug II on the display and operator control unit.
2. Pull off plug on the navigation unit.
3. Check lead from navigation unit plug pin 5 to plug II pin 4 for short to B+.
Test point 4
Data lead, DSP-PCM
Open circuit/short to ground
Short to B+
Signal disturbance
Fault code 23
Open circuit/short to ground
1. Pull off plug II on the display and operator control unit.
2. Pull off plug I (18-pole) on the amplifier.
3. Check lead from plug II pin 14 to plug I pin 17 for continuity and short to ground.
Short to B+
1. Pull off plug II on the display and operator control unit.
This is a source reference. Confirm exact model applicability in the original material.