Code Definition

B2429 — A/C Post Heater Sensor #2 Circuit Short to Ground

System: Body  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About B2429

B2429 is a generic (obd-ii standard) body diagnostic trouble code. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B2429 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) in the monitored circuit; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: Body (B) codes are often stored in the body control module, airbag module, or climate module. A basic OBD-II tool usually will not read body codes — an enhanced or OEM-level scan tool is typically required.

Because B2429 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The HVAC control module monitors post heater air temperature sensor #2, a thermistor positioned in the air ducting downstream of the heater core to verify the temperature of heated air being delivered to the cabin. DTC B2429 is set when the module detects the signal voltage from post heater sensor #2 has dropped below the expected range, indicating the signal circuit is shorted to ground. Because the thermistor resistance falls as temperature rises, a continuous near zero signal voltage mimics an unrealistically high temperature condition. When this code is active, automatic climate control fu...

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