P0748: Transmission pressure control solenoid A has an electrical fault

Pressure control solenoid A electrical / transmission fluid pressure solenoid electrical

Severity: Inspect soon

The code points to the solenoid that sets line pressure in the automatic transmission. Owner reports on Kia models describe hard shifts and shuddering, and the reference says the transmission may go into fail-safe, so it should be checked before it damages the transmission.

It gets more serious if:

Stop: Stop driving and have the car towed if the transmission will not move the car, slips badly or the engine stalls when it shifts. Slipping with low pressure wears clutches quickly.

Source: how we rate severity

P0748 in short

P0748 means the transmission computer sees an electrical fault in pressure control solenoid A, the valve that sets fluid pressure for shifting. Wiring, the solenoid itself or a valve body problem are the usual causes, and some Kia and Hyundai models have computer updates. Hard shifts and limp mode are common, so get it checked soon.

The transmission computer controls fluid pressure with a pressure control solenoid. P0748 sets when the computer sees an electrical fault in solenoid A or its circuit, for example an open or short in the wiring or a failed solenoid coil.

Pressure sets how firmly the clutches grab, so a fault often shows up as hard or flared shifts, shuddering, or the transmission holding one gear. The reference page says the transmission may also go into fail-safe (limp) mode.

Makers have treated the code in different ways. Hyundai's bulletin for the 2007 Elantra groups P0748 with other solenoid codes caused by incorrect solenoid operation. Two 2011 Sorento owners report a transmission computer reprogram after a dealer found P0748. The code is not a diagnosis of the solenoid alone, so the circuit and fluid need checking too.

Most likely causes

Cause 1: Wiring, connector or solenoid fault in the pressure control circuit
Common general cause
Why it ranks here
The code is defined as an electrical fault in this solenoid circuit, and the reference lists damaged, shorted, disconnected or corroded wiring and a defective solenoid first.
What would change this
Rises if the connector or harness shows damage or the solenoid resistance is out of specification. Falls if the circuit and solenoid test good.
How to test the transmission control module (tcm)
Cause 2: Transmission computer software that needs an update (some models)
Supported by vehicle data
Why it ranks here
Two 2011 Kia Sorento owners say a dealer reprogrammed the transmission computer after finding P0748, and Kia's bulletin is quoted by number in both. Complaint narratives only, so the bulletin is not confirmed.
What would change this
Rises if a dealer finds an open update for your VIN. Falls if the computer is already current and the code returns.
How to test the transmission control module (tcm)
Cause 3: Worn valve body or clogged fluid passages
Common general cause
Why it ranks here
The reference lists a defective valve body or clogged passages after the solenoid and wiring. It ranks lower because it needs the transmission opened up.
What would change this
Rises if the fluid is dark, burnt or has debris on the pan magnet. Falls if the fluid is clean and the solenoid circuit is at fault.
Cause 4: Degraded transmission fluid
Common general cause
Why it ranks here
The reference lists degraded fluid as a cause. It is a cheap thing to check before parts are replaced.
What would change this
Rises if the fluid is burnt, low or overdue for service. Falls if it is clean and at the right level.
Cause 5: Failed transmission or engine computer
Possible — needs testing
Why it ranks here
The reference calls control module failure rare. It is only worth considering after the wiring and solenoid have tested good.
What would change this
Rises if the circuit tests good and the code returns after a software update. Falls if a wiring or solenoid fault is found.
How to test the transmission control module (tcm)

What to test first

Start at step 1. Each result tells you what it means and where to go next.

Step 1: Read the transmission module with a scan tool that can see it, and note any other transmission codes and the freeze-frame data.
Low riskTool: scan tool that reads the transmission module
- IfP0748 is stored alone, or with other solenoid codes
  It meansAsk a dealer whether a computer update applies, then check the fluid.
  Go to step 2
- IfOther transmission or network codes are stored
  It meansDiagnose the other codes first; they may share a power or wiring cause.
  Go to step 3
Step 2: Ask a dealer whether your VIN has an open transmission computer update or bulletin for P0748.
Low risk
- IfAn update applies and the computer is not at the latest level
  It meansUpdate the software and retest before replacing parts.
  Points to: Transmission computer software that needs an update (some models)
- IfNo update applies
  It meansCheck the fluid and the circuit next.
  Go to step 3
Step 3: With the vehicle level, check the transmission fluid level and condition using the method in the owner's manual.
Use caution
Warning:The engine and transmission can be hot and moving parts are close to the dipstick or fill point. Some transmissions have no dipstick and must be checked by a shop.
- IfThe fluid is low, burnt or has debris
  It meansFluid condition may be part of the fault; service it and look for a valve body problem.
  Points to: Degraded transmission fluid
- IfThe fluid is clean and at level
  It meansTest the solenoid circuit.
  Go to step 4
Step 4: Inspect the transmission connector and harness for damage, corrosion or a loose pin, then test the solenoid circuit and solenoid resistance against the service information for your vehicle.
Best left to a shopTool: multimeter, service information
Warning:Many transmissions need the pan or connector area opened, with hot fluid, and back-probing live circuits can short pins. A shop with service information should do it.
- IfWiring or connector damage is found, or the solenoid is out of specification
  It meansThe circuit or solenoid is at fault.
  Points to: Wiring, connector or solenoid fault in the pressure control circuit
- IfThe circuit and solenoid test good
  It meansSuspect the valve body or the control module.
  Points to: Worn valve body or clogged fluid passages

Symptoms

Hard or flared shifts, especially while slowing to a stop
Shuddering when the engine is warm
Check engine light, sometimes with a transmission warning
Transmission stuck in one gear or in limp mode Gets more serious: stop and have it checked.
Engine sputters or nearly stalls as the transmission downshifts Gets more serious: stop and have it checked.

How to fix

Step 1: Read all stored codes with a scan tool that can see the transmission module and write down any other codes.
Step 2: Ask a dealer whether an open transmission computer update or bulletin applies to your VIN.
Step 3: Check the transmission fluid level and colour using the method in the owner's manual.
Warning:The engine and transmission can be hot. If your vehicle has no dipstick, leave this to a shop.

Parts and cost context

Transmission control module (TCM):Software updates are often tried before a solenoid or control module is replaced. Labour varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Kia

2011 · Sorento
Supported by vehicle data
Two owners of 2011 Sorentos report a dealer found P0748, described as pressure control solenoid A electrical fault, and reprogrammed the transmission computer under a Kia bulletin they number TRA038. One still had hard shifts afterwards. These are owner narratives; the bulletin was not seen.

Hyundai

2007 · Elantra
Supported by vehicle data
Hyundai bulletin TSB-09-AT-011 lists P0748 with other solenoid codes for the 2007 Elantra. Whether it is still current is not verified.

TSB-09-AT-011Status unverified
ATA solenoid diagnostic trouble codes
2007elantra · issued December 17, 2009 · NHTSA 10030884
Lists P0748 among transaxle solenoid codes and says incorrect solenoid operation can give a check engine light and 3rd-gear fail-safe. The NHTSA summary does not say what the repair is.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

All Transmission codes

P0748 questions

Is it safe to drive with P0748?

Short, gentle trips are usually possible, but hard shifts, slipping or limp mode mean the transmission is not getting the right pressure. Get it checked soon and stop if it stalls or will not move.

Does P0748 always mean a bad solenoid?

No. The code covers the solenoid circuit, so wiring, fluid, the valve body or software can be the cause. Two Kia owners say a software update was the fix their dealer tried first.

Sources and review

P0748 trouble code summary — TroubleCodes.net
NHTSA complaint ODI 10406469 (2011 Kia Sorento) — NHTSA Office of Defects Investigation
NHTSA complaint ODI 11080071 (2006 Kia Spectra) — NHTSA Office of Defects Investigation
NHTSA complaint ODI 10863738 (2011 Kia Sorento) — NHTSA Office of Defects Investigation
TSB-09-AT-011: ATA solenoid diagnostic trouble codes (2007 Elantra) — Hyundai Motor America , December 17, 2009
Bulletin 003-04: MIL on with DTC P0748, P0798, P0985 or P0986 (2004 Camry) — Toyota Motor Sales , May 26, 2004

Last reviewed: October 16, 2026
Written by: Saurabh K.
Editorial review: Pending
Technician review: Technician review pending

This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error

Severity: Inspect soon

Most likely causes

Cause 1: Wiring, connector or solenoid fault in the pressure control circuit

Cause 2: Transmission computer software that needs an update (some models)

Cause 3: Worn valve body or clogged fluid passages

Cause 4: Degraded transmission fluid

Cause 5: Failed transmission or engine computer

What to test first

Step 1: Read the transmission module with a scan tool that can see it, and note any other transmission codes and the freeze-frame data.

Step 2: Ask a dealer whether your VIN has an open transmission computer update or bulletin for P0748.

Step 3: With the vehicle level, check the transmission fluid level and condition using the method in the owner's manual.

Step 4: Inspect the transmission connector and harness for damage, corrosion or a loose pin, then test the solenoid circuit and solenoid resistance against the service information for your vehicle.