Many transmission controllers feed their solenoids through internal high-side switches, called actuator supply A and B. Ford's 6R140 splits its Transmission Solenoid Power Control into two wires: TSPC-A powers shift solenoids A, C and E (fault P0657), TSPC-B powers SSB, SSD, TCC and line pressure control (P2669). Because both share one internal switch, any fault switches off all seven solenoids, leaving park, reverse, neutral and 5th gear with full line pressure; Ford lists P2669 with MIL. In GM's 16OBDG08 tables for Silverado/Sierra the TCM flags an open supply 2 when several solenoids on it read open at once while the supply line stays high; GM's 2023 TCM test checks at power-down and logs it as Type A. P2670 and P2671 cover low and high faults.
Medium severity. Can I keep driving?If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
Symptoms
- Transmission stuck in a fixed gear (failsafe)
- Harsh engagements due to maximum line pressure
- MIL or transmission warning on
Most likely causes
- Open supply wire or connector between module and transmission bulkhead
- Damaged internal transmission harness or lead frame
- High-side switch inside the controller failed
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: hard
- It can trigger limp mode.
- It affects emissions.
What each character of P2669 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 6: Control modules and outputs
- 69: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2669?
If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
What causes code P2669?
The most common causes are: open supply wire or connector between module and transmission bulkhead; damaged internal transmission harness or lead frame; high-side switch inside the controller failed.
Related codes
- P2670Actuator Supply Voltage B Circuit Low
- P2671Actuator Supply Voltage B Circuit High
- P0657Actuator Supply Voltage A Circuit/Open
- P2684Actuator Supply Voltage C Circuit/Open
Sources
- newtonnet.co.uk: fordobd2012
- fordservicecontent.com: obd summary diesel 2023
- gsi.ext.gm.com: 16OBDG08 Transmission Diagnostics
- gsi.ext.gm.com: 23OBDG07
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.