For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
PAL B+ | -- | 1 | -- | --
Left Audio Signal (+) | 2 | 3 | 2 | --
Right Audio Signal (+) | 4 | 5 | 4 | --
Audio Common Signal (-) | 6 | 7 | 6 |
PAL Ground | -- | 1 | -- | --
1. PAL module inoperative. No Communication with PAL or DRR, XM can not be selected from radio. BCM DTC U2172, Radio DTC U0194, LED on PAL does not illuminate. 2. No sound from left speakers when PAL or XM™ is sourced on radio. 3. No sound from left speakers when only PAL is sourced on radio.

4. No sound from right speakers when PAL or XM™ is sourced on radio.

5. No sound from right speakers when only PAL is sourced on radio.

6. No sound from all speakers when PAL or XM™ is sourced on radio.

7. No sound from all speakers when only PAL is sourced on radio.

### Circuit Description

The Apple iPod® is connected to the personal audio link (PAL) through a dedicated interface cable. The cable allows the iPod the ability to share serial data communication, audio signals, power and ground with the vehicle. The T-harness used to connect the PAL module shares the same power and grounds as the radio. The audio signal circuits are shared with the Digital Radio Receiver audio circuits. The PAL module receives Data communication by connecting inline with the DRR.

### Diagnostic Aids

• | After PAL is installed, it is only possible to communicate with the DRR when the radio is ON and XM band selected.

• | If radio is OFF, or tuned to any other band a NO COMM message for DRR is displayed on Tech2 (Vehicle DTC Check).

• | PAL module maintains a persistent B1000 code that cannot be cleared, and does not affect operation.

• | If PAL module loses power or ground, BCM and Radio set DTCs for loss of communication with DRR.

• | The iPod® interface connector is susceptible to vibration and movement damage. It is recommended that excessive movement of the iPod® and cable be avoided while driving.

### Reference Information

#### Schematic Reference

Radio/Navigation System Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Radio/Audio System Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

Note: Verify that the iPod® is in good working order and visually inspect the iPod® connector cavity for any signs of damage before performing this diagnostic. Verify the most up to date software has been downloaded from http://www.apple.com/support/ipod/ to the iPod® before performing this diagnostic.

1. Tune to a strong AM or FM station and verify each speaker is producing clear and even sound, with no distortion.

⇒ | If any speaker is not producing sound or the sound produced is distorted, refer to Speaker Malfunction.

2. Ignition ON, Observe the PAL red LED lamp. Verify the red LED lamp is illuminated.

⇒ | If the PAL red LED is not illuminated, go to Circuit/System Testing.

3. Set the radio to the iPod® interface menu and attempt to operate audio from the iPod®.
4. Inspect the interface harness at the connection to the iPod® and verify that audio quality from the iPod® is not changed when the harness is bent in multiple directions.

⇒ | If the audio changes quality or drops out, inspect the iPod® connector cavity or interface cable for damage. If no damage found, replace the iPod® interface cable.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the PAL module.
2. Test for less than 5 Ω between terminal 9 and ground.

⇒ | If greater than specified value, test the ground circuit for an open/high resistance.

3. Ignition ON, verify that a test lamp illuminates between terminal 16 and ground.

⇒ | If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.

4. Ignition OFF, reconnect the harness connector at the PAL module.
5. Disconnect the X2 harness connector at the radio.
6. Radio ON, iPod sourced and playing, test for a varying mV AC voltage between the following signal circuit terminals listed below and ground.

• | Left audio signal (+) - terminal 1

• | Right audio signal (+) - terminal 2

• | Audio common signal (-) - terminal 9

⇒ | If the varying mV A/C voltage is not present, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuits tests normal, replace the PAL module.

7. If all circuits test normal, replace the radio.

### Circuit/System Testing

#### PAL LED Indicator Malfunction

1. Ignition OFF, disconnect the PAL harness connector.
2. Ignition ON, verify that a test lamp illuminates between the PAL B+ circuit terminal and ground.

⇒ | If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.

3. Verify that a test lamp illuminates at both PAL ground circuit terminals and B+.

⇒ | If the test lamp does not illuminate, test the ground circuits for an open/high resistance.

4. If all circuits test normal, replace the PAL.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | For PAL replacement, refer to Ipod® interface installation instructions.

• | Control Module References for Radio replacement and programing.