Fault code P1906 – a step-by-step guide to diagnosing and fixing it

The meaning of error code P1906 – Kickdown Pull Relay Open or Short Circuit to Ground

P1906: Causes, signs and repairs

Error code P1906 is displayed and the check engine light is on - what does this mean?

The DTC P1906 is recognized by the OBD system and indicates a fault in the transmission control module, specifically in the pressure control or pressure sensor of the automatic transmission. This manufacturer-specific error code mainly occurs in General Motors vehicles and affects the electronic transmission control system.

What can cause this fault code?

Defective transmission oil pressure sensor
Damaged wiring to the pressure sensor
Loose or corroded plug connections
Defective transmission control unit (TCM)
Clogged transmission oil filter
Low transmission oil level
Defective pressure control valves in the transmission housing
Internal transmission damage or wear

What symptoms occur in parallel with fault code P1906?

Shifting problems: Jerky or delayed gear changes
Emergency running program: The transmission only shifts into certain gears
Loss of power: Reduced engine power and poor acceleration
Irregular shift points: Transmission shifts too early or too late
Transmission vibrations: Noticeable vibrations while driving
Increased fuel consumption: Inefficient transmission control leads to increased fuel consumption

How can the problem with error code P1906 be rectified?

Repairing error code P1906 requires a systematic diagnosis of the transmission control system.
Check the transmission oil level and quality, change the oil and replace the filter if necessary
Remove the transmission oil pressure sensor, clean it or replace it with a new sensor
Check all plug connections to the transmission control unit for tight fit and corrosion
Test the wiring between the TCM and pressure sensor for continuity and short circuits using a multimeter
Read out transmission control unit with diagnostic device and have it replaced if defective
Clean or replace pressure control valves in the transmission housing (transmission workshop required)

FAQ - Frequently asked questions about DTC P1906

Can I continue driving with error code P1906?

Short distances are possible, but the error code P1906 should be rectified promptly. The transmission can switch to emergency mode, which can lead to further damage.

How much does it cost to repair error code P1906?

The repair costs for the P1906 code vary between 150-800 euros, depending on the cause. A new pressure sensor costs around 80-200 euros, while a TCM replacement can cost up to 1,500 euros.

How can I diagnose the error code P1906 myself?

You can read out the P1906 code using an OBD scanner. First check the transmission oil level and the plug connections. Specialist workshop equipment is required for more in-depth diagnostics.

Is the error code P1906 a serious problem?

Yes, the P1906 trouble code indicates problems in the transmission control system. If left untreated, it can lead to costly transmission damage and should be rectified promptly at a specialist workshop.

What tools do I need for the P1906 repair?

For basic diagnostics, you will need an EOBD scanner, multimeter and basic tools. More complex repairs to the transmission require special tools and the expertise of a transmission workshop.

Does error code P1906 return after the repair?

If the root cause is repaired correctly, the P1906 fault code should not return. If it does, this indicates overlooked problems or new defects in the transmission system.

Vehicles in which fault code P1906 occurs most frequently

Error code P1906 is a manufacturer-specific DTC that occurs mainly in General Motors vehicles and indicates problems with the transmission pressure control, but is most common in the following vehicles:

Chevrolet: Malibu, Impala, Equinox, Traverse, Silverado (2008-2018)
Buick: LaCrosse, Enclave, Regal, Verano (2008-2017)
GMC: Acadia, Terrain, Sierra, Yukon (2007-2016)
Cadillac: SRX, CTS, Escalade, XTS (2008-2019)
Pontiac: G6, G8, Torrent (2006-2010)
Saturn: Outlook, Aura, Vue (2007-2010)
Oldsmobile: Aurora (late models until 2003)
If the code P1906 occurs in your vehicle, a prompt diagnosis at a qualified workshop is recommended. Especially in older GM vehicles with higher mileage, the transmission system should be serviced regularly to avoid such error codes. Most repairs can be carried out successfully with the correct diagnosis, and preventive maintenance such as regular transmission oil changes can significantly reduce the occurrence of the P1906 code.

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