Secondary and Configurable Customer Controls: Diagnosis Cadillac STS I facelift

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

Begin the system diagnosis with the Diagnostic System Check - Vehicle . The Diagnostic System Check - Vehicle will provide the following information

1. The identification of the control modules which command the system
2. The ability of the control modules to communicate through the serial data circuit
3. The identification of any stored DTCs and their status

The use of the Diagnostic System Check - Vehicle will identify the correct procedure for diagnosing the system and where the procedure is located.

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(ref-338149-S41903538652009081700000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-338149-S37154416862009081700000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-338149-S02595537362009081700000) provides an overview of each diagnostic category.

Diagnostic Fault Information

Conditions for Running the DTC

1. Voltage supplied to the module is in the normal operating voltage range of 9-16 volts.
2. IPM in Accessory, Run or Crank power modes.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the left and right steering wheel control switches.
2. Ignition ON, test for B+ between the voltage reference circuit terminal 1 and ground. If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the IPM.
3. Test for B+ between the voltage reference circuit terminal 1 and the signal circuit terminal 4. If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
4. Ignition OFF, disconnect the X3 harness connector at the IPM.
5. Test for infinite resistance between the signal circuit terminal 4 and ground. If less than the specified value, test the signal circuit for a short to ground.
6. Ignition ON, test for less than 1 volt between ground and the voltage reference circuit terminal 5 at the left steering wheel control switch. If greater than the specified range, test the voltage reference circuit for a short to voltage
7. Ignition ON, test for infinite resistance between ground and the voltage reference circuit terminal 5 at the left steering wheel control switch. If not the specified value, test the voltage reference circuit for a short to ground.
8. Test for less than 1 ohm between the voltage reference circuit terminal 5 at the left steering wheel control switch and the voltage reference circuit terminal 1 at the right steering wheel control switch. If greater than the specified range, test the voltage reference circuit for a an open/high resistance.
9. If all circuits test normal, test or replace the left or right steering wheel control switch.

Component Testing

1. Disconnect the harness connector at the right or left steering wheel control switch.
2. Connect a DMM between terminals 1 and 4 of either the left or right steering wheel control switch. If any of the resistance measurements for the individual switches are not within the specified resistance values, replace the right steering wheel control switch.

Left Steering Wheel Switch Resistance

Right Steering Wheel Switch Resistance

Visual/Physical Inspection

1. Inspect for aftermarket devices which may affect the operation of the Steering Wheel Controls System. Refer to «Checking Aftermarket Accessories»(ref-338151-S01119782592009081700000) .
2. Inspect for easily accessible or visible system components for obvious damage or conditions which may cause the symptom.

Symptom List

Refer to Steering Wheel Controls Inoperative in order to diagnose the symptom.

1. Perform the «Diagnostic System Check - Vehicle»(ref-338149-S41903538652009081700000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-338149-S37154416862009081700000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-338149-S02595537362009081700000) provides an overview of each diagnostic category.

Diagnostic Aids

1. Ensure the primary controls of the associated component are functioning properly before diagnosis of the steering wheel controls.
2. Review schematic when testing switch resistance values.

1. Ignition OFF, disconnect the harness connector at the left and right steering wheel control switches.
2. Ignition ON, test for B+ between the voltage reference circuit terminal 1 and ground. If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the IPM.
3. Test for B+ between the voltage reference circuit terminal 1 and the signal circuit terminal 4. If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
4. Ignition OFF, disconnect the X3 harness connector at the IPM.
5. Test for infinite resistance between the signal circuit terminal 4 and ground. If less than the specified value, test the signal circuit for a short to ground.
6. Ignition ON, test for less than 1 volt between ground and the voltage reference circuit terminal 5 at the left steering wheel control switch. If greater than the specified range, test the voltage reference circuit for a short to voltage
7. Ignition ON, test for infinite resistance between ground and the voltage reference circuit terminal 5 at the left steering wheel control switch. If not the specified value, test the voltage reference circuit for a short to ground.
8. Test for less than 1 ohm between the voltage reference circuit terminal 5 at the left steering wheel control switch and the voltage reference circuit terminal 1 at the right steering wheel control switch. If greater than the specified range, test the voltage reference circuit for a an open/high resistance.
9. If all circuits test normal, test or replace the left or right steering wheel control switch.

1. Disconnect the harness connector at the right or left steering wheel control switch.
2. Connect a DMM between terminals 1 and 4 of either the left or right steering wheel control switch. If any of the resistance measurements for the individual switches are not within the specified resistance values, replace the right steering wheel control switch.

Left Steering Wheel Switch Resistance

Right Steering Wheel Switch Resistance