Diagnostic Test

CHECK FOR ACTIVE DTC
1. Turn the ignition on.
2. Using the scan tool, record and erase the Radio DTCs.
3. Turn the Radio on.
4. With the scan tool, read the active DTCs.
  Did the DTC return?
  
  Yes
  - Go To 2
  No
  - Perform the appropriate INTERMITTENT CONDITION procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
CHECK THE STATUS OF THE REMOTE RADIO SWITCHES IN THE RADIO
1. Do not press either remote radio switch.
2. Hands off the Steering Wheel.
3. With the scan tool, monitor the "PRESSED/NOT PRESSED" status of the remote radio switches in the Radio data display.
  Do any remote radio switch always show "PRESSED"?
  
  Yes
  - Go To 3
  No
  - Replace the Radio in accordance with Service Information.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST or BODY VERIFICATION TEST (EV) .
CONTINUE TO CHECK THE STATUS OF THE REMOTE RADIO SWITCHES IN THE RADIO
NOTE:
Do not press either remote radio switch.
1. Start the engine and allow it to idle.
2. With the scan tool, continuously monitor the "PRESSED/NOT PRESSED" status of the remote radio switches in the Radio data display while performing the test in the following order:
  - Hands on the Steering Wheel turning slowly to full left, full right, and back to center.
  - Hands on the Steering Wheel apply slight straight ahead pressure while turning slowly to full left, full right, and back to center.
  - Hands on the Steering Wheel pulling back with slight pressure while turning slowly to full left, full right, and back to center.
  - If equipped, adjust the steering column up and down in all positions, and repeat the above process.
3. Turn the engine off.
  Did the remote radio switch status change during testing?
  
  Yes
  - Go To 5
  No
  - Go To 4

CHECK THE REMOTE RADIO SWITCHES

The ignition must be off.
Remove the remote radio switches from the steering wheel according to service information.

Use an ohmmeter to check the switch resistances as shown in the Remote Radio Switch Test chart.

REMOTE RADIO SWITCH TEST (Approximate Values)
Switch	Switch Position	Minimum Resistance (kilohms)	Nominal Resistance (kilohms)	Maximum Resistance (kilohms)
Right	Volume Up	6.732	6.8	6.868
Right	Volume Down	14.850	15	15.151
Right	Mode Advance	0	0	0
Left	Seek Up	1.188	1.2	1.212
Left	Seek Down	3.267	3.3	3.333
Left	Pre-Set Station Advance	0.465	0.47	0.474

Are the remote radio switch resistances in specifications?

Yes

Go To 5

Replace the Remote Radio Switches in accordance with Service Information.
Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST or BODY VERIFICATION TEST (EV) .

CHECK THE (X20) MUX CIRCUIT BETWEEN THE STEERING WHEEL SWITCHES AND STEERING ANGLE SENSOR
1. The ignition must be off when checking the circuit for damage.
2. Using the wiring diagram, isolate the MUX circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit. Note: Use the wiring diagram as a guide to follow the path of the circuit from the Steering Wheel Switches to the Steering Angle Sensor to the BCM.
3. Inspect the MUX circuit for chafed, pierced, pinched, or partially broken wires.
4. Inspect the MUX connectors and terminals for broken, bent, pushed out, spread, corroded, contaminated or the presence of foreign conductive materials on connector pins and terminals.
  Was any visual damage found to the MUX circuit?
  
  Yes
  - Repair the damaged MUX circuit as needed.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST or BODY VERIFICATION TEST (EV) .
  No
  - Go To 6
ISOLATE AND CHECK THE (X20) MUX CIRCUIT FOR A SHORT TO GROUND BETWEEN THE STEERING WHEEL SWITCHES AND STEERING ANGLE SENSOR
1. The ignition must be off when checking a circuit for continuity to ground.
2. Connect the negative lead of the DVOM to a known good ground.
3. With the positive lead of the DVOM, probe the circuit being tested at the component harness connector and check for continuity between the circuit and ground.
  NOTE:
  When probing a circuit at an Electronic Control Unit (ECU) harness connector, always use an appropriate back probing tool to prevent any possible damage to the ECU terminals.
  
  NOTE:
  There should be no continuity between ground and the circuit being tested.
  
  Is there continuity between ground and the circuit being tested?
  
  Yes
  - Repair the circuit for a short to ground. Use the wiring diagram as a guide to trace the circuit and look for any in-line connectors to help isolate the location of the short.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST or BODY VERIFICATION TEST (EV) .
  No
  - Go To 7
ISOLATE AND CHECK THE (X20) MUX CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT AT THE STEERING ANGLE SENSOR HARNESS CONNECTOR
1. The ignition must be off when performing a resistance check to find a short between circuits.
2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit being tested. At this time leave all in-line connectors connected. Note: Use the wiring diagram as a guide to follow the path of the circuit.
3. Connect one lead of the DVOM to the circuit being tested at the ECU harness connector.
4. With the other lead of the DVOM probe all other circuits at the ECU harness connector.
  NOTE:
  When probing a circuit at an Electronic Control Unit (ECU) harness connector, always use an appropriate back probing tool to prevent any possible damage to the ECU terminals.
  
  NOTE:
  With the circuit isolated there should be no continuity between the circuit being tested and any other circuit.
  
  Is there continuity between the circuit being tested and any other circuit?
  
  Yes
  - Repair the short between the circuits that have continuity. Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors to help isolate the location of the short.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST or BODY VERIFICATION TEST (EV) .
  No
  - Go To 8
CHECK THE (X20) MUX CIRCUIT BETWEEN THE STEERING WHEEL SWITCHES AND STEERING ANGLE SENSOR
1. The ignition must be off when checking the circuit for damage.
2. Using the wiring diagram, isolate the MUX circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit. Note: Use the wiring diagram as a guide to follow the path of the circuit from the Steering Wheel Switches to the Steering Angle Sensor to the BCM.
3. Inspect the MUX circuit for chafed, pierced, pinched, or partially broken wires.
4. Inspect the MUX connectors and terminals for broken, bent, pushed out, spread, corroded, contaminated or the presence of foreign conductive materials on connector pins and terminals.
  Was any visual damage found to the MUX circuit?
  
  Yes
  - Repair the damaged MUX circuit as needed.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST or BODY VERIFICATION TEST (EV) .
  No
  - Go To 9
ISOLATE AND CHECK THE (X20) MUX CIRCUIT FOR A SHORT TO GROUND BETWEEN THE STEERING ANGLE SENSOR AND BCM
1. The ignition must be off when checking a circuit for continuity to ground.
2. Connect the negative lead of the DVOM to a known good ground.
3. With the positive lead of the DVOM, probe the circuit being tested at the component harness connector and check for continuity between the circuit and ground.
  NOTE:
  When probing a circuit at an Electronic Control Unit (ECU) harness connector, always use an appropriate back probing tool to prevent any possible damage to the ECU terminals.
  
  NOTE:
  There should be no continuity between ground and the circuit being tested.
  
  Is there continuity between ground and the circuit being tested?
  
  Yes
  - Repair the circuit for a short to ground. Use the wiring diagram as a guide to trace the circuit and look for any in-line connectors to help isolate the location of the short.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST or BODY VERIFICATION TEST (EV) .
  No
  - Go To 10
ISOLATE AND CHECK THE (X20) MUX CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT AT THE BCM HARNESS CONNECTOR
1. The ignition must be off when performing a resistance check to find a short between circuits.
2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit being tested. At this time leave all in-line connectors connected. Note: Use the wiring diagram as a guide to follow the path of the circuit.
3. Connect one lead of the DVOM to the circuit being tested at the ECU harness connector.
4. With the other lead of the DVOM probe all other circuits at the ECU harness connector.
  NOTE:
  When probing a circuit at an Electronic Control Unit (ECU) harness connector, always use an appropriate back probing tool to prevent any possible damage to the ECU terminals.
  
  NOTE:
  With the circuit isolated there should be no continuity between the circuit being tested and any other circuit.
  
  Is there continuity between the circuit being tested and any other circuit?
  
  Yes
  - Repair the short between the circuits that have continuity. Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors to help isolate the location of the short.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST or BODY VERIFICATION TEST (EV) .
  No
  - Replace the Body Control Module (BCM) in accordance with the Service information.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST or BODY VERIFICATION TEST (EV) .