Shift Solenoid "A" Control Circuit High
The DURAMAX-P0974 (Duramax) diesel fault code means: Shift Solenoid "A" Control Circuit High. This is a serious severity code.
- Keep driving?
- Yes, with caution
- DIY difficulty
- intermediate
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What Are the Symptoms of DURAMAX-P0974?
- Check Engine Light on
- Harsh, delayed or erratic shifts
- Transmission may hold a single gear
What Causes DURAMAX-P0974? (Most Likely First)
- Open control wire or a short to voltage High
- Failed shift solenoid "A" Moderate
- Corroded connector Moderate
- Control module driver fault Low
Can I Still Drive with DURAMAX-P0974?
Yes, with caution. DURAMAX-P0974 is rated serious severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
What does P0974 mean on a Duramax?
P0974 means Shift Solenoid "A" Control Circuit High. The control module has detected a higher than expected voltage on the shift solenoid "A" circuit.
Is P0974 a Duramax-specific code?
No. P0974 is a generic OBD-II code defined by SAE J2012, so it means the same thing on any vehicle that sets it. The exact conditions GM uses to set it on its diesels are in GM service information.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose DURAMAX-P0974?
Inspect the shift solenoid "A" connector and wiring.
Check the shift solenoid "A" resistance against the service specification.
Check the circuit for an open and a short to voltage, then command it with a scan tool.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines P0974 as a generic OBD-II code)
P0974 on Other Platforms
The same code ID appears across other engines, vehicles, and equipment. Diagnostic flow varies by platform — see the matching breakdown:
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