Skip the auto shop - Our mechanics make house calls

Q: It threw a code 21 , throttle position sensor bad code. i replaced it and the code went away but i still have no spark.

asked by on

six monthes ago i replaced the cranshaft sensor because it just died and would not start. finally figured out it was the security key. fixed that ran no problem. 2 weeks ago it started to run bad again. i checked for codes and got a bad camshaft sensor and throttle postion sensor are bad codes because it would not stat again. i replaced them bothe. the codes went away but still noe spark. whats next

My car has 187000 miles.
My car has an automatic transmission.

Hello and thank you for contacting YourMechanic. The problems that you are encountering with your vehicle, could be caused by the harness to the Throttle Position Sensor (TPS) or the computer itself.

Check the harness to the TPS for any debris or any corrosion. Hook up a paperclip to the harness and turn on the key. Use a multimeter and check for voltage at the pins of the harness. Make sure that the ground on the sensor is grounded and has no resistance. If you find that the harness is having too much resistance, then I recommend having the main engine harness replaced. If you have replaced the harness and still have the same problems, then the computer will need to be flashed or replaced.

I recommend having a professional, like one from YourMechanic, come to your home to diagnose your car’s no start condition before replacing any parts.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  • Home
  • Questions
  • It threw a code 21 , throttle position sensor bad code. i replaced it and the code went away but i still have no spark.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Car shuddering

When the vehicle stability assistance (VSA) control module detects wheel spin, it sends a request to the modulator unit to apply brake pressure to slow the spinning wheel. At the same time, it sends a signal to the traction control...

Q: Car shutting off after 5 minutes of being started.

This may be a result of a dirty or failing idle air control valve. The idle air control valve reads the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and...

Q: I changed out ignition coil and spark plugs and the car isn't starting anymore. 2008 Infiniti G37

Hello. If the work was done with the correct parts then it should be as simple as something that may have been left loose. If the engine is not cranking over then it may be as simple as a low...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...