Throttle response issue

Tiny
67NADA
  • MEMBER
  • 2007 VOLVO XC70
  • 2.4L
  • 5 CYL
  • TURBO
  • 4WD
  • AUTOMATIC
  • 180,000 MILES
When you start the car and attempt to drive away, there is no throttle response. Pumping or pressing the accelerator pedal has no effect. After multiple tries, the engine surges to full throttle, returns to idle on release, and is fine for the remainder of the drive cycle, be it 5 blocks or 500 miles. Letting it idle for a while or revving it in neutral before setting out does not help. It's like a recurring temporary limp mode with no codes.
Friday, November 27th, 2020 AT 1:00 PM

3 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
If there are no codes then this is most likely a throttle body issue. You have what is called an electronic throttle body meaning there is no cable connecting the pedal and throttle plate. You have a pedal sensor that tells the PCM what the position of the pedal is and then the throttle is opened the same amount.

So more then likely if you had a pedal sensor issue or a throttle sensor issue it would set a code. So if there are no codes then the actuator in the throttle body is the faulty part.

I attached the process to replace this for your review. Thanks
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Friday, November 27th, 2020 AT 1:35 PM
Tiny
67NADA
  • MEMBER
  • 3 POSTS
Thanks for the quick response. I know that the Marelli units on the V70s were problematic. The smallest bit of dirt buildup at the plate area would make the idle fluctuate. Just wiping them clean with a rag would fix it. Cleaning a really dirty one on my Rover produced no change. I believe that this unit is a Bosch, and I haven't seen anything about similar problems here. This seems very much a drive cycle issue that I would suspect to be processor related, as it never occurs except after fresh startup.
Thanks
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Friday, November 27th, 2020 AT 1:58 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Great update and information. I don't disagree so let us know what turns up or what other info you need and we are glad to help. Thanks
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Saturday, November 28th, 2020 AT 5:09 PM

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