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 Descriptor

DTC B3670: Pump Motor Temperature Sensor Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

B+ - Folding Top Control Module

1

1

--

--

Temperature Sensor 5-Volt Reference

B3670

B3670

B3670

--

Temperature Sensor Signal

B3670

B3670

B3670

--

Ground - Folding Top Control Module

--

1

--

--

1. No communication with the FTC module.

Circuit/System Description

The folding top control (FTC) module monitors the folding top pump motor temperature, checking the temperature once every 300 milliseconds. The FTC module supplies a 5-volt reference and monitors the sensor low reference voltage from the thermistor located in the folding top pump motor. As the pump motor warms up and the temperature increases, the thermistor resistance will increase. The FTC module monitors the voltage drop across the thermistor and uses it to calculate the temperature of the pump motor. When the FTC module detects that the temperature is above the maximum operating range, it will set this DTC.

Conditions for Running the DTC

    • The FTC module must be powered and can not have B1327 or B1328 set as active DTCs for this DTC to set. The battery voltage is between 9-16 volts.
    • The FTC module is in Accessory, RUN, or RAP.

Conditions for Setting the DTC

    • The FTC module detects that the folding top pump motor temperature is greater than 115°C (239°F).
    • The FTC module detects that the folding top pump motor temperature is less than -20°C (-4°F) +/-5°C.

Action Taken When the DTC Sets

    • Stores a current and history DTC B3670 in the FTC module.
    • The FTC module will allow the top to be closed but not opened until the until the condition is cleared.
    • A class 2 message is sent to the driver information center, TOP MOTOR OVER TEMP, as the folding top switch is pressed.

Conditions for Clearing the DTC

    • This DTC will become history once the pump motor temperature is below 90°C (194°F).
    • A history DTC will clear after 50 consecutive ignition cycles without a fault present.

Diagnostic Aids

    • This DTC may set under normal operating conditions. Each time the folding top is moved to the open and closed positions it will cause the temperature of the pump motor to increase. Therefore, numerous cycles of the power folding top may raise the temperature to the point for which this DTC will set. Because this DTC can set under normal operating conditions, the following conditions must also be considered when diagnosing this DTC:
      • High ambient temperature--A high ambient temperature will limit the number of times the system will operate.
      • Low ambient temperature--A low ambient temperature will limit the number of times the system will operate.
    • This DTC may set in low temperature conditions that is below the recommended temperature for folding top operation. Refer to Pump Motor and Temperature Sensor in Power Folding Top Description and Operation.
    • The following conditions may cause an intermittent malfunction:
       - An intermittent sticking or binding linkage condition can cause excessive current draw resulting in a temperature out of range.
       - The folding top pump motor or thermistor is shorted internally.

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

  1. Ignition OFF, disconnect the X431 inline harness connector.
  2. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal B8 and ground.
  3. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the FTC module.
    If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the FTC module.
  4. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal B8 and the signal circuit terminal B7.
  5. 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 FTC module.
    If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the FTC module.
  6. If all circuits test normal, replace the folding top pump motor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Folding Top Pump with Motor Replacement
    •  Control Module References for FTC module replacement, setup, and programming