P0748 on Chevrolet
Pressure Control Solenoid "A" Electrical
P0748 on Chevrolet vehicles indicates pressure control solenoid "a" electrical. Au7o has documented this code across 6 Chevrolet models — most commonly on Avalanche, Camaro, S-10. 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 Avalanche(1 issue)
- 4L60E Transmission 3-4 Clutch Failure / Slipping2002-2013
Avalanches equipped with the 4L60E automatic commonly lose 3rd and 4th gear due to 3-4 clutch pack burnout, a known factory weak point. The long fluid circuit feeding the 3-4 clutch leaks at the input housing (steel shaft galls the aluminum bore) and at the 2-4 servo, so the clutches slip, overheat, and burn. Symptoms are smooth 1-2 shifts but a flare/neutral feeling into 3rd, often with delayed engagement.
Chevrolet Camaro(1 issue)
- 4L60E automatic transmission 3-4 clutch pack and sun shell failure1994-1999
The electronically controlled 4L60E four-speed automatic behind the V6, LT1 and LS1 Camaros has two well-known failure points. The 3-4 clutch pack burns out first: the drum has limited space and thin factory friction plates that wear rapidly under heat and load, so the trans shifts fine through 1st and 2nd but slips or feels like neutral going into 3rd/4th, often with RPM flare on the 2-3 shift. The second is the 'sun shell' (reaction shell), a stamped part prone to fracturing at the hub — when it breaks you typically lose 2nd, 4th and Reverse at once, dropping to 1st and 3rd only. Heat is the primary accelerant on these transmissions; degraded fluid speeds both failures.
Chevrolet S-10(1 issue)
- 4L60E Automatic Transmission 3-4 Clutch and Sunshell Failure1993-1999
S-10s with the electronically controlled 4L60E four-speed automatic (introduced in trucks for 1993, behind the 4.3L) commonly suffer 3-4 clutch pack burnup and a cracked/stripped factory sunshell ('reaction shell'). The OE 3-4 clutch discs wear and burn, causing slip when shifting to 3rd/overdrive; the weak sunshell fractures at the hub and causes loss of reverse plus 2nd/4th. Related weak points include the plastic 1-2 accumulator and the 2-4 band. Heat and towing accelerate failure.
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 6 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 6 Chevrolet models: Avalanche, Camaro, S-10, Silverado 1500, Suburban, Tahoe.