GM Service Manual Online
For 1990-2009 cars only

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 B3674 01: Movable Roof Control Valve 1 Circuit short to battery

DTC B3674 02: Movable Roof Control Valve 1 Circuit short to ground

DTC B3674 04: Movable Roof Control Valve 1 Circuit open circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

B+, FTC Module X1 Terminal 24

1

1

--

--

B+, FTC Module X1 Terminal 26

B1335 03, B3860 02

B1335 03

--

--

12-Volt Reference

B1395 02

B1296 06, B3669 06

--

--

Serial Data, FTC Module X1 Terminal 1

1

--

1

--

Serial Data, FTC Module X1 Terminal 2

1

--

1

--

Serial Data, FTC Module X1 Terminal 11

B316A 02

2

B316A 01

--

Serial Data, FTC Module X1 Terminal 23

B316A 02

3

B316A 01

--

Signal, FTC Module X1 Terminal 4

B3685 59, B1010 08

B3685 59

--

--

Signal, FTC Module X1 Terminal 5

4

4

--

--

Signal, FTC Module X1 Terminal 10

B3602 02

4

--

--

Signal, FTC Module X1 Terminal 16

B3683 59, B1010 08

B3683 59, B1010 08

--

--

Signal, FTC Module X1 Terminal 17

B366C 59

B1010 08

--

--

Signal, FTC Module X1 Terminal 22

B3602 02

4

--

--

Signal, FTC Module X2 Terminal 7

B366D 59

B366D 59

--

--

Signal, FTC Module X2 Terminal 8

B366A 59

B366A 59

--

--

Signal, FTC Module X2 Terminal 11

B3669 06

B3669 06

B3669 01

--

Signal, FTC Module X2 Terminal 12

B1395 02

B367B 59

--

--

Signal, FTC Module X2 Terminal 17

B367F 59, B1010 08

B367F 59, B1010 08

--

--

Signal, FTC Module X2 Terminal 18

B1307 59

B1307 59

--

--

Signal, FTC Module X2 Terminal 19

B366E 59

B366E 59

--

--

Signal, FTC Module X2 Terminal 20

B366B 59

B366B 59

--

--

Signal, FTC Module X2 Terminal 23

B1296 06

B1296 06

B1296 01

--

Signal, FTC Module X2 Terminal 24

B367A 59

B1395 02

--

--

Valve 1 Control

B3674 02

B3674 04

B3674 01

--

Valve 2 Control

B3674 02

B3674 04

B3674 01

--

Folding Top Pump Motor Direction A Voltage Control

B3680 02

B3680 04

B3680 01

--

Folding Top Pump Motor Direction B Voltage Control

B3680 02

B3680 04

B3680 01

--

Low Reference Circuit

--

B3674 01, B3675 01, B1010 08

4

--

Ground, FTC Module X1 Terminal 25

--

B1345 04

--

--

Ground, FTC Module X1 Terminal 27

--

1

--

--

1. No Communication With FTC Module

2. Passenger Side Windows Inoperative During Top Operation

3. Driver Side Windows Inoperative During Top Operation

4. Folding Top Malfunction

Circuit/System Description

The folding top uses electronically controlled valves to control the flow of hydraulic fluid. The folding top control (FTC) module controls Valve 1 (V1) by supplying voltage to the valve. The FTC Module also monitors the control circuit of V1 for proper operation.

Conditions for Running the DTC

The FTC module is active.

Conditions for Setting the DTC

B3674 01

A short to voltage on the control circuit of V1.

B3674 02

A short to ground on the control circuit of V1.

B3674 04

An open on the control circuit or low reference circuit of V1.

Action Taken When the DTC Sets

The top is disabled.

Conditions for Clearing the DTC

The fault is no longer present and the top completes one cycle.

Reference Information

Schematic Reference

Folding Top Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Power Folding Top 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 Testing

B3674 01

Test the control circuit of V1 for a short to voltage. If the circuit test is normal, replace the FTC module.

B3674 02

Test the control circuit of V1 for a short to ground. If the circuit test is normal, replace the FTC module.

B3674 04

  1. Ignition OFF, disconnect the harness connector at V1.
  2. Test for less than 5.0 ohm between the low reference circuit terminal 2 and ground.
  3. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the FTC module.
  4. Connect a test lamp between the control circuit terminal 1 and ground.
  5. Ignition ON, command V1 on with a scan tool. The test lamp should illuminate.
  6. If the test lamp does not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the FTC module.
  7. If all circuits test normal, replace V1.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Folding Top Pump with Motor Replacement
    •  Folding Top Control Module Replacement