Diagnostic Instructions

DTC Descriptors

DTC B3646 04: Steering Wheel Scroll Wheel Right Circuit Open

DTC B3646 5A: Steering Wheel Scroll Wheel Right Stuck

DTC B3646 08: Steering Wheel Scroll Wheel Right 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

B3646 04

The SCCM detects that the right scroll wheel circuit is open.

B3646 5A

The SCCM detects that the right scroll wheel is stuck for greater than 60 seconds.

B3646 08

The SCCM detects that the right scroll wheel resistance is out of range.

Action Taken When the DTC Sets

The SCCM will ignore the switch command.

Conditions for Clearing the DTC

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

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 scroll wheel switch. The reading should be Volume Up and Volume Down 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.