P0842 on GMC
Transmission Fluid Pressure Sensor/Switch 'A' Circuit Low
P0842 on GMC vehicles indicates transmission fluid pressure sensor/switch 'a' circuit low. Au7o has documented this code across 1 GMC model — most commonly on Acadia. The transmission fluid pressure sensor/switch 'A' circuit voltage is below the expected range (too low / shorted to ground). Typical repair costs on GMC range from $1,800 to $4,500, depending on the specific model and root cause.
Common Causes of P0842
- •Sensor signal shorted to ground
- •Faulty pressure sensor/switch A
- •Corroded/damaged connector
- •Internal TCM fault
P0842 on GMC by Model
GMC Acadia(1 issue)
- 6T70/6T75 3-5-Reverse Wave Plate Fracture — Loss of 3rd, 5th and Reverse2007-2012
The 35R clutch wave plate inside the 6T70/6T75 six-speed transaxle cracks and fractures, allowing the 35R clutch piston to overstroke and leak apply pressure. The result is a hard flare or slip in 3rd and 5th gear and eventually a complete loss of reverse. Failures typically begin after about 25,000 miles and are extremely common on the early Lambda Acadia; GM eventually extended coverage on the wave plate to 10 years/120,000 miles. Debris from the broken plate circulates through the transmission, so a simple plate swap is often not enough on high-mileage units.
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View P0842 across all makes →Frequently Asked Questions
What does P0842 mean on GMC?▼
P0842 stands for "Transmission Fluid Pressure Sensor/Switch 'A' Circuit Low." The transmission fluid pressure sensor/switch 'A' circuit voltage is below the expected range (too low / shorted to ground). On GMC specifically, this code is documented across 1 model.
What causes P0842 on GMC vehicles?▼
Common causes on GMC: Sensor signal shorted to ground, Faulty pressure sensor/switch A, Corroded/damaged connector, Internal TCM fault. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0842 on a GMC?▼
Repair costs on GMC range from $1,800 to $4,500, depending on the specific model and root cause.
Which GMC models have P0842 documented?▼
Au7o has documented P0842 on 1 GMC model: Acadia.