Catalyst temperature sensor internal failure shorting the signal circuit to ground; Chafed or damaged signal wire from the sensor to the PCM touching chassis ground; Corroded or loose connector pins at the sensor or PCM causing a short; Moisture intrusion into the sensor connector or wiring harness creating a ground path; Aftermarket sensor with incorrect resistance characteristics installed previously; PCM internal fault pulling the signal circuit low (rare but possible)

DTC codes / GM codes / P1482

P1482 · GMCatalyst Temperature Sensor Circuit Shorted Low

Q: What does code P1482 mean?

Catalyst Temperature Sensor Circuit Shorted Low. P1482 on a GM vehicle means the powertrain control module (PCM) has detected a short to ground on the catalyst temperature sensor signal circuit, reading a voltage lower than the expected range. The PCM uses this sensor to monitor the catalytic converter's internal temperature for proper efficiency and to protect the converter from overheating, so a low short prevents accurate temperature feedback.

P1482 on a GM vehicle means the powertrain control module (PCM) has detected a short to ground on the catalyst temperature sensor signal circuit, reading a voltage lower than the expected range. The PCM uses this sensor to monitor the catalytic converter's internal temperature for proper efficiency and to protect the converter from overheating, so a low short prevents accurate temperature feedback.

SystemPowertrain

Code typeGM specific

SeverityMedium

Fix difficultyIntermediate

AreaAuxiliary emission controls

Symptoms you may notice

Illumination of the check engine light (malfunction indicator lamp) with no other noticeable symptoms in many cases
Reduced engine performance or power if the PCM enters a limp-home mode
Slightly higher fuel consumption due to altered fuel control strategies
Failed emissions test because the catalyst monitor cannot run
In rare cases, a rough idle or hesitation if the short affects shared sensor reference circuits
No visible signs under the hood, as the fault is electrical and internal to the wiring or sensor

Common causes, most likely first

Catalyst temperature sensor internal failure shorting the signal circuit to ground
Chafed or damaged signal wire from the sensor to the PCM touching chassis ground
Corroded or loose connector pins at the sensor or PCM causing a short
Moisture intrusion into the sensor connector or wiring harness creating a ground path
Aftermarket sensor with incorrect resistance characteristics installed previously
PCM internal fault pulling the signal circuit low (rare but possible)

How to diagnose and fix it

Connect a scan tool and record freeze-frame data to confirm P1482 is active and not history
Visually inspect the catalyst temperature sensor wiring and connector for chafing, corrosion, or moisture
Disconnect the sensor and measure resistance across its terminals; compare to GM specifications for the ambient temperature
Check the signal circuit for continuity to ground with the sensor disconnected; repair any short found
If wiring is intact, substitute a known-good sensor and clear the code to see if it returns
Verify the PCM connector pins are clean and tight, and check for any signs of internal PCM damage
After repair, clear codes and run the catalyst monitor to confirm the fix and ensure no pending codes return

Don't replace the converter for P1482

A shorted catalyst temperature sensor often sets P1482 without turning on the check engine light immediately; the PCM may need two consecutive trips to illuminate the lamp, so a single occurrence can be a ghost.
The catalyst temperature sensor on GM vehicles is sometimes called a bed temperature sensor, and its signal wire is easily pinched during transmission or exhaust work, leading to a short that mimics a failed sensor.
A short to ground on the signal circuit can also be caused by a failed sensor that internally shorts only when hot, so a cold resistance check may pass; testing while the exhaust is at operating temperature is more reliable.
Do not confuse P1482 with P0420 or P0430; those codes indicate catalyst efficiency below threshold, while P1482 is strictly an electrical circuit fault, and replacing the converter will not fix a wiring short.
If the sensor is replaced and the code returns immediately, inspect the harness near the exhaust hanger and any aftermarket alarm or remote start wiring that may have tapped into the ground circuit.

Can I keep driving with P1482?

You can usually continue driving with P1482 because the engine will run in a default strategy, but avoid heavy loads or sustained high speeds that could overheat the converter without temperature feedback. Have the fault diagnosed soon to prevent potential catalytic converter damage and to pass emissions testing.

Tools that help

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Guidance is general and written for GM vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.