P2734 code definition
In P2724 codes, the vehicle’s PCM has detected a problem in a particular solenoid circuit or electronic pressure control solenoid. Computer controlled automatic transmissions use specific degrees of hydraulic pressure for torque converter lockup points and shifting; the PCM controls pressure via one or more electronic pressure control solenoids.
What a P2734 code means
The parameters for a P2734 code may vary greatly between manufacturers and models, but they all rely on calculations from:
- Throttle position
- Engine speed
- Vehicle speed
This data helps determine the degree of pump pressure needed for efficient operation. If fluid pressure doesn’t agree with the fluid pressure needed, a code will be stored and the dashboard malfunction indicator lamp (MIL) will illuminate. In some instances, multiple failure cycles may be needed to illuminate the MIL.
Causes of P2734 code
- Faulty electronic pressure control solenoid
- Blockage inside internal transmission fluid passages
- Mechanical failures of internal transmission parts
- Low fluid level
- Dirty or contaminated fluid
- Faulty transmission control module
- Faulty PCM
Symptoms of P2734 code
- Failure to shift
- Failure of torque converter clutch to engage or disengage
- Limp-in mode
- Harsh shifts
- Slipping transmission
- Overheating transmission
- Stored code
- Illuminated MIL or Check Engine Light
Note that the P2724 code may be accompanied by other codes related to torque converter clutch, lockup, gear ratio, shift solenoid or transmission slippage.
Diagnosing the P2734 code
A code reader and digital volt/ohmmeter will be needed. The OBD-II uses a computerized control system to compare engine drivability inputs with vehicle speed, engine/turbine speed and transmission output speed, determining transmission fluid pressure via the pressure control solenoid and pump.
Check for dirty, contaminated or burnt transmission fluid, and top off transmission if needed using recommended fluid.
Burnt fluid, as always, can be a sign of overheating and catastrophic internal mechanical failure. Drop transmission pan and check for clutch material or shavings. If such debris is found, a total rebuild, fluid flush/replacement and new torque converter are recommended. If no debris, check internal wiring and connectors, looking for shorted or burned wiring.
In most cases, shorted or burned wiring or connectors will necessitate full replacement of internal transmission harness.
If wiring, connectors and components appear OK, connect the scanner to the diagnostic connector and record all stored trouble codes. This information can be helpful in diagnosing intermittent problems that may have led up to the hard code.
Clear codes and operate vehicle to see if code returns. If code doesn’t return, it could be an intermittent problem, which can be tricky to diagnose and may need to be allowed to worsen for a proper diagnosis.
After clearing codes, fill the transmission with correct fluid and test drive at normal operating temperature. If codes don’t return, the problem may have been caused by low fluid level/pressure. If the code returns along with slippage or delays in engagement, use a manual pressure gauge to check pump pressure.
Find a hydraulic pressure diagram for the vehicle and thread your gauge onto the correct opening on the transmission housing, then compare your readings to manufacturer’s specs. Transmission pump replacement will require you to drop the transmission.
If the code returns but the transmission seems to operate normally, look into reference voltage and ground signals for electronic pressure control solenoid, and compare against manufacturer’s specs.
Disconnect any related control modules and check for continuity and resistance in reference voltage and ground circuits. Repair/replace system circuits and connectors and retest system. Test any other related circuits and the solenoid itself for resistance and continuity, and compare readings against specs.
Repair/replace any circuits, connectors or components that don’t comply with specs.
Retest entire system; if all circuits seem intact, connect scanner to the diagnostic connector and see if you can manually activate the pressure control solenoid.
If the control solenoid is operating properly and all circuits are within manufacturer’s specs, the problem could be the torque converter, high pressure pump or PCM. If the solenoid fails to engage manually, replace the solenoid and then retest the entire transmission control system.
Additional considerations for P2734 code
Sensor issues can be hard to track down, and often can mean several things. A methodical process-of-elimination method is key, rather than just replacing parts. One thing’s for sure, though – transmission problems only get worse as time and miles go on. A P2724 code and its symptoms mean that you should not keep driving that vehicle. Get it into a shop for qualified diagnosis and repair as soon as possible.
Need help with a P2734 code?
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