P0789–P078E Shift Timing Solenoid A Intermittent
The fault comes and goes, which points at a connection that only breaks under vibration, heat or load.
Can you drive it? The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.
Which code is which
Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.
| Code | Definition | Severity |
|---|---|---|
P0789 | Shift Timing Solenoid A Intermittent | Investigate soon |
P078E | Shift Timing Solenoid B Intermittent | Investigate soon |
The definition
P0789: Shift Timing Solenoid A Intermittent.
P0789 is a powertrain code (the engine or gearbox), defined by the SAE standard - it means the same thing on any make of car, and any generic OBD-II reader will decode it.
What to check first
Cheapest and fastest checks first:
- Read the freeze-frame data stored with the fault - engine speed, load and temperature at the moment it logged tell you whether this happens cold, hot or under load.
- Check the connector at the part for corrosion, and that it is fully seated.
- Clear the code and see whether it returns, and under what conditions.
What actually causes this on a VAG
Same shift timing solenoid circuit as the codes above, but the fault came and went - the control unit saw something wrong briefly and it recovered. Intermittent transmission faults are usually connections, a moving harness or a voltage problem rather than a component that has failed outright. You may notice nothing at all, or an occasional harsh change or brief limp home that clears at the next restart.
Most likely causes, in order
- Connector or pin fault at the gearbox. Oil wicking into the plug, corroded or spread pins, or a connector that is not fully latched. Inspect it, and reproduce the fault with a wiggle test while the live data is on screen - that is what turns a guess into a diagnosis.
- Temperature related - only hot, or only cold. Read the freeze frame stored with the code before clearing it. Gearbox oil temperature, engine speed and road speed at the moment it set will tell you whether to test the car warmed through or from cold, and let you try to reproduce it deliberately.
- Voltage dips from a tired battery or a poor earth. Momentary drops set circuit codes across several modules. Look for faults with similar timestamps in other control units, and have the battery and charging tested - it is cheap and it rules out a lot.
- A solenoid on its way out. Solenoids often go intermittent before they fail permanently. If the fluid, wiring and supply are all good and the fault keeps returning under the same conditions, valve body work becomes the reasonable next step.
Worth knowing: Write down or photograph the freeze frame data before you clear this code. The conditions it occurred under are the only real clue an intermittent fault gives you, and clearing it throws them away. Nobody should be replacing a mechatronic on the strength of one intermittent entry.
Reading the code is the easy part
A code names the circuit that complained. What tells you why is watching the sensor behind it while the engine runs — and that is where a code reader stops and a diagnostic tool starts.
VAGPULSE reads every module in a VW, Audi, Skoda or SEAT — not just the engine — shows the live measuring blocks behind this fault, gives you the freeze-frame conditions it was logged under, and clears it once you have fixed it. It also does what a generic OBD reader cannot on a VAG: service resets, coding, adaptations, and Stage 1–3 flashing with your original file saved first.
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Common questions
What does P0789 mean?
P0789 means Shift Timing Solenoid A Intermittent. The fault comes and goes, which points at a connection that only breaks under vibration, heat or load.
Can I drive with P0789?
The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.