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.

### DTC Descriptors

DTC B3644 5A: Steering Wheel Remote Control Channel Up Switch Stuck
DTC B3644 08: Steering Wheel Remote Control Channel Up Switch Circuit Resistance Range/Performance

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Left Steering Wheel Control Switch Signal | 1 | B3647 08, B3648 08, B3649 04, B3649 08 | 1 | B3647 5A, B3648 5A, B3649 5A
Right Steering Wheel Control Switch Signal | 1 | B3644 08, B3645 08, B3646 04, B3646 08 | 1 | B3644 5A, B3645 5A, B3646 5A
Low Reference | -- | 1 | 1 | --
1. Steering Wheel Controls Inoperative

### Circuit/System Description

The steering column control module (SCCM) supplies voltage to the audio steering wheel control multiple momentary contact switches and monitors the return signal. Each switch is associated to a set resistance value, when pressed a specific voltage drop occurs through a series of resistors unique to that switch. The SCCM identifies the selection, then sends a serial data message that is received by the component controlled, activating the feature.

### Conditions for Running the DTC

The ignition is ON.

### Conditions for Setting the DTC

#### B3644 5A

The SCCM detects that the channel up switch is stuck for greater than 60 seconds.

#### B3644 08

The SCCM detects that the channel up switch resistance is out of range.

### Action Taken When the DTC Sets

The SCCM will ignore the switch command.

### Conditions for Clearing the DTC

• | A current DTC clears when the malfunction is no longer present.

• | A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

### Reference Information

#### Schematic Reference

Steering Wheel Secondary/Configurable Control Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Steering Wheel Controls 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

Ignition ON, observe the scan tool Right Steering Remote Control Status parameter while pressing and releasing the channel up switch. The reading should be Up-Key identifying when the switch pressed, and No Key Pressed when the switch is released.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
2. Ignition OFF, test for less than 2.0 ohms between the low reference circuit terminal 3 and ground.

⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the SCCM.

3. Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal 6 and ground.

⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the SCCM.

⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the SCCM.

4. If all circuits test normal, test or replace the right steering wheel control switch.

### Component Testing

1. Disconnect the harness connector at the right steering wheel control switch.
2. Connect a DMM between terminals 3 and 6 of the 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.

Function Switch | Minimum Resistance Value | Maximum Resistance Value
--- | --- | ---
Scroll Wheel Up | 60.8 Ohms | 64.8 Ohms
Scroll Wheel Down | 160.5 Ohms | 164.5 Ohms
Up Key/Station Seek | 359.7 Ohms | 363.7 Ohms
Down Key/Station Seek | 919 Ohms | 923 Ohms
No Switch Pressed | O.L. | O.L.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Steering Wheel Control Switch Assembly Replacement

• | Control Module References for SCCM replacement, setup, and programming