Shift Timing Solenoid A Intermittent
Code P0789 indicates an intermittent fault in the shift timing solenoid A circuit. This solenoid controls hydraulic pressure to engage and disengage clutches and bands for gear shifts. An intermittent signal suggests a loose connection, damaged wiring, or a failing solenoid that works sporadically, leading to unpredictable transmission behavior.
01. Most Common Causes
- Faulty shift solenoid A
- Damaged or corroded wiring/connectors
- Low or contaminated transmission fluid
- Internal transmission mechanical failure
02. Symptoms You Will Notice
- Erratic or harsh shifting
- Transmission slipping
- Check Engine Light illuminated
- Transmission stuck in limp mode
03. Step-by-Step Diagnosis
Step 1: Scan for codes and check freeze frame data.
Step 2: Inspect transmission fluid level and condition.
Step 3: Visually check wiring and connectors to solenoid A for damage or corrosion.
Step 4: Test solenoid resistance and operation using a multimeter or scan tool.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended as intermittent shifting can cause sudden loss of power or transmission damage. Drive only to a repair shop.
How much does it cost to fix?▼
Repair costs range from $150 to $400, depending on whether the solenoid or wiring needs replacement and labor rates.