Code P0502, vehicle speed sensor "a" low, Hold warning light blinking and Check Engine Light on?

Tiny
MALLYBOY
  • MEMBER
  • 2013 CHEVROLET AVEO
  • 1.4L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 75,678 MILES
This vehicle, when cold after cranking, will be driving fine and when hot, it stops shifting gears and when I diagnosed it, it shows P0502: Vehicle Speed Sensor. Then I disconnected the sensor connector and checked for power using test lamp, there was power, and I used DMM and checked for signal and there was 10.50-volts on signal line of the connector. Then I checked for ground, and there was ground. Could it be the speed sensor being faulty? And how do I remove it from the transmission?
Friday, January 27th, 2023 AT 1:08 PM

9 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,097 POSTS
Hi,

I would be happy to help, but I need some confirmation. According to my manual, the code is specific to a manual transmission. See pic 1 below.

I'm not sure if by accident you selected automatic, so let me know. If it is a manual, the diagnostics are provided. Let me know which you have, and I see what I can find on the output speed sensor.

Take care,

joe

See pics below.
Images (Click to make bigger)
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Was this
answer
helpful?
Yes
No
Saturday, January 28th, 2023 AT 9:38 PM
Tiny
MALLYBOY
  • MEMBER
  • 323 POSTS
Hi,

The vehicle has an automatic transmission.
I take out time to inspect the vehicle yesterday and I came with the following observations
1. I unplugged the Input Shaft Speed Sensor, and the hold warning lamp went off and when you crank and engage gear, the gear will engage smoothly without hard shift.
2. I also noticed that the 2-fault codes that normally return back are P0502 and U0100- lost communication with TCM/ECM.
So, I need a communication diagram of TCM and ECM together with junction connector X105 and X205 location, let me trace out where communication fails.
Thanks
Was this
answer
helpful?
Yes
No
Saturday, January 28th, 2023 AT 10:24 PM
Tiny
MALLYBOY
  • MEMBER
  • 323 POSTS
Hi!
There's a short to voltage between the input shaft speed sensor and the transmission solenoid. I need a diagram of the transmission solenoids and for input shaft speed sensor to separate them and solve the problem.
Was this
answer
helpful?
Yes
No
Sunday, January 29th, 2023 AT 12:42 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,097 POSTS
Hi,

The only schematics I have are the OEM ones. Take a look through what I attached and let me know if that is what you needed.

Take care,

Joe
Image (Click to make bigger)
Thumb
Was this
answer
helpful?
Yes
No
Sunday, January 29th, 2023 AT 3:13 PM
Tiny
MALLYBOY
  • MEMBER
  • 323 POSTS
This didn't show how cables run from TCM to solenoid assembly and how they enter into each solenoid.
Was this
answer
helpful?
Yes
No
Sunday, January 29th, 2023 AT 11:05 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,097 POSTS
Are you looking for a schematic or a routing diagram?

Joe
Was this
answer
helpful?
Yes
No
Monday, January 30th, 2023 AT 4:23 PM
Tiny
MALLYBOY
  • MEMBER
  • 323 POSTS
Routing diagram, the p0502 always returns.
Was this
answer
helpful?
Yes
No
Monday, January 30th, 2023 AT 9:17 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,097 POSTS
Hi,

As far as routing through the vehicle, I have no manual that provides that information. Also, the code you provided only shows up for a manual transmission, so I asked the boss. He questioned if it is a Sonic, but the code still comes up for a manual transmission.

I attached schematics for an automatic transmission. Let me know if it helps.

Joe

See pics below.
Images (Click to make bigger)
Thumb
Thumb
Was this
answer
helpful?
Yes
No
Tuesday, January 31st, 2023 AT 5:42 PM
Tiny
MALLYBOY
  • MEMBER
  • 323 POSTS
This diagram is not bright, try to brighten it and resend it and resend.
Was this
answer
helpful?
Yes
No
Tuesday, January 31st, 2023 AT 9:41 PM

Please login or register to post a reply.

Related Check Engine Light Content

Code Read Retrieval/Clear Chevrolet
VIDEO
Code Read Retrieval/Clear Chevrolet
In­struc­tional re­pair video
Check Engine Light
GUIDE
Check Engine Light
Why is my check en­gine or ser­vice en­gine soon turned on? In this guide we talk about what this is as­so­ci­ated with this no­to­ri­ous light, what it is used for and what you...
VIEW MORE