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DTC codes / Chrysler codes / P1534

P1534 · ChryslerA/C High Side Temperature Sensor Low Voltage

P1534 on Chrysler vehicles means the powertrain control module (PCM) has detected a low voltage signal from the air conditioning (A/C) high side temperature sensor, which is a thermistor that reports refrigerant temperature on the high-pressure side of the system. The PCM expects a voltage within a specific range as the sensor's resistance changes with temperature, and a sustained low voltage tells the PCM the circuit is shorted to ground or the sensor has failed.

SystemPowertrain
Code typeChrysler specific
SeverityMedium
Fix difficultyIntermediate
AreaVehicle speed, idle control and auxiliary inputs

Symptoms you may notice

  • The air conditioning may stop cooling or blow warm air because the PCM disables the compressor clutch to protect the system.
  • The A/C compressor clutch may fail to engage at all when the code is active.
  • The check engine light (malfunction indicator lamp) illuminates on the dashboard.
  • The A/C blower may still run normally, but the air is not chilled.
  • Often no symptoms besides the warning light, especially if the fault is intermittent and the PCM has not yet disabled the compressor.
  • In some cases the cooling fans may run continuously or the A/C request may be ignored by the PCM.

Common causes, most likely first

  1. A short to ground in the signal wire between the A/C high side temperature sensor and the PCM.
  2. A failed A/C high side temperature sensor that has internally shorted and reads a permanently low resistance.
  3. Corroded, loose, or damaged connector terminals at the sensor or at the PCM, causing a low-voltage signal.
  4. A chafed or pinched wire harness rubbing against a metal component and grounding the signal circuit.
  5. Moisture intrusion into the sensor connector or wiring, creating a partial short to ground.
  6. A faulty PCM that incorrectly interprets a normal sensor signal, though this is the least likely cause.

How to diagnose and fix it

  1. Scan all modules and record freeze-frame data for P1534 to confirm the fault is current and not history.
  2. Visually inspect the A/C high side temperature sensor, its connector, and the wiring harness for damage, corrosion, or chafing.
  3. Disconnect the sensor and measure its resistance with a multimeter, comparing the reading to the expected value for the ambient temperature.
  4. With the sensor disconnected and the key on, measure voltage on the signal wire at the sensor connector to check for a short to ground.
  5. If the signal wire shows low voltage with the sensor disconnected, isolate the circuit by disconnecting the PCM and checking for continuity to ground on the signal wire.
  6. Repair any shorted wire, replace damaged connector terminals, or replace the A/C high side temperature sensor as needed.
  7. Clear the diagnostic trouble codes and verify the A/C system operates correctly with live sensor data showing a plausible temperature.

What the A/C high side sensor really does

  • Many technicians replace the A/C high side temperature sensor without checking the signal wire for a short to ground, which is actually the most common cause of this code on Chrysler vehicles.
  • A low voltage signal can also be caused by a poor ground reference at the PCM, so verify the PCM ground connections before condemning the sensor.
  • The A/C high side temperature sensor is sometimes confused with the A/C pressure transducer, but they are separate components and set different codes.
  • On some Chrysler models, the sensor shares a reference voltage or ground with other sensors, so a fault in a shared circuit can set P1534 along with other codes.
  • The PCM may disable the A/C compressor clutch when this code is set, so the driver may notice a lack of cooling even though the sensor fault itself does not affect engine performance.

Can I keep driving with P1534?

You can usually drive the vehicle safely with this code because it primarily affects the air conditioning system, but avoid using the A/C until the fault is repaired to prevent potential compressor damage from operating without proper temperature feedback. If the check engine light is flashing or other symptoms appear, stop driving and seek professional diagnosis.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

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

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