Engine-Codes - Gmc - P151C GMC

P151C GMC - A/C Conditioning Low Side Refrigerant Pressure Sensor Not Plausible

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3  What is this?
Table of contents

P151C GMC Possible Causes

  • Low refrigerant
  • Faulty Low Side Pressure Sensor
  • Low Side Pressure Sensor harness is open or shorted
  • Low Side Pressure Sensor circuit poor electrical connection

How is the P151C GMC code repair?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

What is the cost to diagnose the P151C GMC code

Labor: 1.0

The cost to diagnose the P151C GMC code is 1.0 hour of labor. The auto repair labor rates vary widely across the country, and even within the same city. Most auto repairs shops charge between $75 and $150 per hour.
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Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P151C GMC Meaning

The Hybrid Powertrain control module (HPCM2) monitors the low side refrigerant pressure through the A/C refrigerant pressure sensor. The HPCM2 supplies a 5 V reference and a low reference to the sensor. Changes in the A/C refrigerant pressure cause the sensor signal to the HPCM2 to vary. When the pressure is high, the signal voltage is high. When the pressure is low, the signal voltage is low. When pressure is too high or too low, the HPCM2 will not allow the activation of the A/C compressor.
To make the P151C Air Conditioning (A/C) Low Side Refrigerant Pressure Sensor Not Plausible DTC evaluation, the HPCM2 compares the A/C Low Side Refrigerant Pressure Sensor reading with the A/C high side refrigerant pressure reading after a dormant soak period.
In addition, to make the P151C Air Conditioning (A/C) Low Side Refrigerant Pressure Sensor Not Plausible DTC evaluation, the HPCM2 also uses the A/C temperature sensor 2 reading.
These two sensors are both in the same environment. The HPCM2 compares the values of these sensors after a dormant soak period. The HPCM2 takes the temperature value and calculates an equivalent pressure for gaseous R134a at that temperature and at the pressure as reported by the Air Conditioning (A/C) Low Side Refrigerant Pressure Sensor and compares these.
DTC P151C sets if both of these comparisons show that the A/C Low Side Refrigerant Pressor Sensor is not in agreement with the other sensors.
To make the DTC P2516 Air Conditioning (A/C) Low Side Refrigerant Pressure Sensor evaluation, the HPCM2 looks for a drop in the pressure value after the compressor has run for a short period after a dormant soak period.

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