P0748 on GMC
Pressure Control Solenoid "A" Electrical
P0748 on GMC vehicles indicates pressure control solenoid "a" electrical. Au7o has documented this code across 1 GMC model — most commonly on Terrain. P0748 is a generic powertrain code meaning the transmission control module has detected an electrical fault — voltage or resistance out of the expected range — in the circuit for pressure control solenoid "A". This solenoid regulates hydraulic line pressure inside an automatic transmission, adjusting how firmly the clutches and bands apply based on speed, load, and throttle position. When the computer can't control the solenoid electrically, the transmission often defaults to maximum line pressure or limp mode, so you may feel harsh or erratic shifts, slipping, delayed engagement when shifting into Drive, or being locked into a single gear. Because it is an electrical-circuit code, the fault is usually in the solenoid itself or its wiring rather than a purely hydraulic problem, though contaminated fluid can damage the solenoid. Continuing to drive with slipping and overpressure shifts can overheat the transmission and lead to expensive internal damage, so this should be repaired promptly.
Common Causes of P0748
- •Failed pressure control solenoid A (open or shorted solenoid windings)
- •Damaged, frayed, or shorted wiring in the solenoid circuit, including the transmission case connector
- •Corroded or loose electrical connectors at the transmission harness
- •Low, dirty, or contaminated transmission fluid degrading or sticking the solenoid
- •Clogged transmission filter or debris in the valve body hydraulic passages
- •Faulty transmission control module or PCM driver circuit (rare)
P0748 on GMC by Model
GMC Terrain(1 issue)
- Start/Stop Transmission Accumulator Endcap Missing Bolts - Fluid Leak & Loss of Propulsion (Recall)2018-2020
On second-gen Terrains, the automatic transmission's start/stop accumulator endcap may have been assembled with missing bolts, allowing transmission fluid to leak. The leak can progress to loss of propulsion and, if fluid contacts an ignition source, a fire risk. GM recall N202313440 (NHTSA 20V-668) covers certain 2018-2020 Terrain and Equinox units - more than 217,000 vehicles in the US and Canada.
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View P0748 across all makes →Frequently Asked Questions
What does P0748 mean on GMC?▼
P0748 stands for "Pressure Control Solenoid "A" Electrical." P0748 is a generic powertrain code meaning the transmission control module has detected an electrical fault — voltage or resistance out of the expected range — in the circuit for pressure control solenoid "A". This solenoid regulates hydraulic line pressure inside an automatic transmission, adjusting how firmly the clutches and bands apply based on speed, load, and throttle position. When the computer can't control the solenoid electrically, the transmission often defaults to maximum line pressure or limp mode, so you may feel harsh or erratic shifts, slipping, delayed engagement when shifting into Drive, or being locked into a single gear. Because it is an electrical-circuit code, the fault is usually in the solenoid itself or its wiring rather than a purely hydraulic problem, though contaminated fluid can damage the solenoid. Continuing to drive with slipping and overpressure shifts can overheat the transmission and lead to expensive internal damage, so this should be repaired promptly. On GMC specifically, this code is documented across 1 model.
What causes P0748 on GMC vehicles?▼
Common causes on GMC: Failed pressure control solenoid A (open or shorted solenoid windings), Damaged, frayed, or shorted wiring in the solenoid circuit, including the transmission case connector, Corroded or loose electrical connectors at the transmission harness, Low, dirty, or contaminated transmission fluid degrading or sticking the solenoid, Clogged transmission filter or debris in the valve body hydraulic passages. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0748 on a GMC?▼
Repair costs vary widely depending on the root cause and specific GMC model.
Which GMC models have P0748 documented?▼
Au7o has documented P0748 on 1 GMC model: Terrain.