B3670: Folding Top Pump Motor Temperature Sensor Circuit (GM)
Severity: low
What it means: B3670 is a GM body code on cars with a power folding hardtop, such as the Cadillac XLR. The folding top module watches a temperature sensor (a thermistor, a resistor that changes with heat) inside the top's hydraulic pump motor. If the motor reads hotter than about 95°C (203°F), or the sensor circuit reads as if it is, the code sets. The dash shows TOP MOTOR OVER TEMP, and the top will close but won't open until the motor cools below about 90°C (194°F).
Safe to drive? Safe to drive. It affects only the folding top, not the engine or brakes. Close the top and let the pump cool before trying again.
Common symptoms
- TOP MOTOR OVER TEMP message
- Top stops partway or won't open
- Top will close but not open
Likely causes, ranked
- Running the top open and closed many times in a row, or very hot or cold weather (can set it normally)DIY
- Binding or sticking top linkage making the pump work harderShop
- Shorted pump motor or temperature sensor inside the pumpShop
- Wiring fault in the sensor circuit or a bad folding top moduleShop
Vehicle-specific notes
- 2004–2009 Cadillac XLR: On XLR-Net, an owner got TOP MOTOR OVERTEMP when raising the top. The dealer quoted about $4,656 for a pump, sensors and a lock, and the owner later had a convertible shop replace the pump for about $2,400. Read the full answer · Source
DIY or shop?
Let it cool and try again. That's the only DIY step for most owners. Wiring tests need a scan tool and meter, and the GM procedure ends with replacing the pump and valve assembly if the circuits test normal.
Before you replace parts
- Close the top and let the pump cool, then retry once.
- Note whether the code comes back after just one or two cycles.
- Have the top linkage checked for binding.
- Have the pump temperature sensor circuit tested before replacing the pump.
Safety / mechanic note
Verify with a mechanic. Low risk to driving. A top stuck partway can leave the car open to weather and theft. A code points to a circuit or system, not always a specific part.