Skip the auto shop - Our mechanics make house calls

Q: Car is running slow, what could it be?

asked by on

The codes I’ve been given are P0502 & P1406. My check engine light is on & my speedometer isn’t working; it’ll get up to what feels like 30 mph & sometimes do a jerking motion/speed up or start to slow down. I've also noticed that on the right side a fan will start up & my car makes struggling noises. I’ve been told to check my Transmission Fluid, but that looks like the proper color & fills to both holes on the dip stick. I’ve had a mechanic come out once for checking the problem & again to fix a possible solution (speed sensor). After the 2nd time, he told me I would need a speed sensor pigtail connector, which I found & need replaced. Any suggestions if that might not work?
My car has an automatic transmission.

A: If you already replaced the sensor then now...

If you already replaced the sensor then now it will need that connector you've mentioned. Replacing it may fix the code P0502. The code P1406 is for the EGR valve position, you would need to have the valve tested to see if it is stuck open or if the valve is bad. Have a pinpoint test done on the code P1406. I suggest to have a qualified technician perform these checks and properly diagnose your trouble codes further. From there they can perform the necessary repairs. Good luck

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!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: no fire going to plugs

Hello. By far the most common cause of this symptom on your vehicle is the ignition control module. This is located inside of the distributor and it can cause a no-crank if it fails. The control module can typically be...

Q: Secondary coil replacement for a 2007 ES 350 Lexus

Hi there. That code is set when the primary or secondary circuit for the specified coil has failed. If you are not experiencing any drivability concerns, then it is most likely that the circuit has not failed to the point...

Q: Check Engine Light is on - code P0350

Hi there. Changing the plugs and coils is definitely a plausible route to take; however, this sounds like you have an open circuit in the wire harness, anywhere from the coils to the ECM. Using a digital volt/ohm meter...

Related articles

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...
How to Renew Your Car Registration in Oklahoma(DELETED)
Having your car registered with the Oklahoma Tax Commission is an important part of driving legally in this state. You will need to do this within 30 days of moving to Oklahoma...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...