P0748 on Chevrolet
Pressure Control Solenoid "A" Electrical
P0748 on Chevrolet vehicles indicates pressure control solenoid "a" electrical. Au7o has documented this code across 3 Chevrolet models — most commonly on Silverado 1500, Suburban, Tahoe. 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. Typical repair costs on Chevrolet range from $1,500 to $3,500, depending on the specific model and root cause.
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 Chevrolet by Model
Chevrolet Silverado 1500(1 issue)
- 4L60E Automatic Transmission 3-4 Clutch Pack and Sun Shell Failure (Slipping, Loss of 3rd/4th Gear)1994-2010
The 4L60E 4-speed automatic behind the half-ton Silverado is notorious for wearing out its 3-4 clutch pack and cracking the input 'sun shell' (reaction sun gear shell) as mileage climbs. Owners report the truck suddenly loses 3rd and 4th gear (revs up but won't pull) while reverse and low gears still work, or a hard grinding/no-move with a fractured sun shell. The 3-4 clutch is the known weak point and often burns up first; the larger input drum on 2004-and-up units also likes to crack internally. This is one of the single most-searched failures for these trucks.
Chevrolet Suburban(1 issue)
- 4L60E Transmission 3-4 Clutch Failure / Loss of 3rd & 4th1994-2006
The 4L60E automatic behind the half-ton Suburban is notorious for burning up the 3-4 clutch pack. The 3-4 apply circuit is long and loses pressure as valve-body bores wear, so the clutches overheat and glaze. Symptoms are slipping in 3rd/4th, a jump from 2nd straight to 4th, or a sudden loss of 3rd and 4th (RPM flares, no forward pull in higher gears while reverse and low gears still work). On 2004+ units the input drum can also crack, and the pot-metal sun-gear shell ("sun shell") strips teeth, causing loss of reverse.
Chevrolet Tahoe(1 issue)
- 4L60E Automatic Transmission 3-4 Clutch Failure (Loss of 3rd/4th Gear)1995-2010
The 4L60E 4-speed automatic behind the Vortec V8s is the single most common major failure on high-mileage Tahoes. The 3-4 clutch pack is the known weak point: its friction plates burn up, and the truck suddenly slips or drops out of 3rd and 4th gear (RPMs flare with no acceleration), leaving effectively only 1st and 2nd. Later-production units (roughly 2004+) used thinner/cheaper clutch material and tend to fail earlier. Contributing factors include worn shift solenoids, a leaking valve body/accumulator, TCC solenoid failure, and neglected/burnt fluid. Many owners hit this between 120k-180k miles.
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View P0748 across all makes →Frequently Asked Questions
What does P0748 mean on Chevrolet?▼
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 Chevrolet specifically, this code is documented across 3 models.
What causes P0748 on Chevrolet vehicles?▼
Common causes on Chevrolet: 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 Chevrolet?▼
Repair costs on Chevrolet range from $1,500 to $3,500, depending on the specific model and root cause.
Which Chevrolet models have P0748 documented?▼
Au7o has documented P0748 on 3 Chevrolet models: Silverado 1500, Suburban, Tahoe.