Control Module VSS Output A Malfunction
The P0608 code means the vehicle's onboard diagnostic system has detected: Control Module VSS Output A Malfunction. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $100 - $1200 (parts and labor)
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What Are the Symptoms of P0608?
- Check Engine Light illuminated
- Speedometer may not work
- Cruise control inoperative
- Transmission may not shift properly
What Causes P0608? (Most Likely First)
- ECM vehicle speed signal output circuit fault Very High
- Damaged wiring from ECM to speedometer/TCM High
- Failed instrument cluster speed input Moderate
- ECM internal VSS output driver failure Low
Can I Still Drive with P0608?
Short distances only. P0608 is rated moderate severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
Can I drive with code P0608?
Drive short distances only. Internal control module errors can cause unpredictable engine behavior.
Does P0608 mean I need a new ECM?
Not always. Some internal module errors can be resolved by reprogramming or reflashing the ECM with factory software. However, hardware failures (RAM, ROM, processor) typically require ECM replacement.
How much does an ECM replacement cost?
ECM replacement typically costs $300-$1500 including the part and programming. The ECM must be programmed with the correct calibration and vehicle options for your specific VIN.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P0608?
-
Check vehicle speed signal at the ECM output pin
-
Verify speedometer operation and compare to GPS speed
-
Check wiring from ECM VSS output to receiving modules
-
Inspect ECM connector pins for damage
-
Replace ECM if internal VSS output driver has failed
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Which Vehicles Commonly Get P0608?
- 2003-2015 Ford F-150
- 2004-2016 Chevrolet Silverado
- 2005-2017 Dodge Ram 1500
- 2002-2014 Toyota Tacoma
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