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Discussion Starter #1
I have a 1995 C280. It only has 126,290 miles on it. I scanned my car and this is what I got:

P0400 exhaust gas recirculation flow
P1170 short term fuel trim malfunction
P1700 up-shift delay switchover valve without function (logic chain)


What is the up-shift delay switchover? Everyone on the posts keeps saying to go buy a new one, but then I search online stores and can’t find anything close to the up-shift delay switchover valve?

Does anyone know another name for the part so I can replace it, and does anyone have a diagram of a 1995 C280 that might help me find my way around under the hood?

Also when I am parked with the car running, if I have my interior air on my car makes a loud kind of clicking sound, or stuttering or putting sound coming from the fan and fan belt area. If I turn off my interior air it gets a little quieter but it still makes a noise. (the noise kind of sounds like a muffled version of a card on a bicycle wheel hitting the spokes, not as clunky but more muffled or something)

Does anyone know how to change the serpentine belt, and how I can change my cars tension pulley? Cause I am assuming that is the reason.


Thanks!
Megan
 

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I have a 1995 C280. It only has 126,290 miles on it. I scanned my car and this is what I got:

P0400 exhaust gas recirculation flow
P1170 short term fuel trim malfunction
P1700 up-shift delay switchover valve without function (logic chain)
P0400 -- Exhaust gas recirculation flow malfunction
  • >Activation requirement CHECK ENGINE lamp:
    --After one "performed" test with failure.
  • Activation of CHECK ENGINE lamp:
    --At start of next trip.
  • Test to detect fault:
    --The EGR logic chain is checed if the following conditions are simultaneously satisfied:
    • • No failure in the electrical activation of the EGR switchover valve
      • Deceleration fuel shut-off operating
      • Closed throttle position recognized
      • Engine speed approximately 1900-2600 RPM and constant
      • Intake manifold pressure less than 325 mbar
      • Momentary intake air temperature >10°C
    After approximately 1 second, the diagnostic module determines the intake manifold pressure. Initiated by the diagnostic module (via the CAN data bus), the engine control module then briefly activates the EGR switchover valve. The intake manifold pressure is evaluated for approximately 3 seconds. The pressure in the intake manifold must drop by at least approximately 15 mbar while the EGR switchover valve is activated
  • P1170 -- Short term fuel trim (self-adaption to fuel mixture)
    • Activation requirement CHECK ENGINE lamp:
      --Two consecutive trips with fault.
    • Activation of CHECK ENGINE lamp:
      --At start of next trip.
    • Test to detect fault:
      --The engine control module checks the short term fuel trim for maximum and minimum limits. When the limits are exceeded, a message is transmitted to the diagnostic module via CAN.
P1700 -- Transmission upshift delay switchover valve withought function (logic chain)
  • Activation requirement CHECK ENGINE lamp:
    --After two consecutive "performed" tests with fault.
  • Activation of CHECK ENGINE lamp:
    --At start of next trip.
  • Test to detect fault
    --The test is performed, if the following conditions are met simultaneously:
    • • No failure in electrical activation of upshift delay switchover valve.
      • Transmission upshift delay active
      • Load below approximately 55%
      • Engine not at idle speed
      • Transmission selector not in Park/Neutral Position.
    The diagnostic module checks the engine RPM at a certain vehicle speed. If a predetermined engine speed threshold is not exceeded, a fault is recognized.
    • ModelKM/H (MPH)RPM202.022 (C220)47-15 (29-32)1750202.028 (C280)42-45 (26-28)2100
Does anyone know how to change the serpentine belt, and how I can change my cars tension pulley? Cause I am assuming that is the reason.
Thanks!
Megan
Hi Megan, don't assume that's causing the problem have it check by a Certified Euro mechanic.

Hope this helps,
JOE55
 

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Discussion Starter #3
I found out that the first 2 codes were from one of my spark plugs not being properly screwed in.

But now the P1700 code keeps coming back.
 

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P1700

Megan,

I had the P-1700 on mine and it was a hose had fallen off of the Vacuum Switch under the hood. The Vacuum Upshift Circuit is the thing that is supposed to (when working) make your car shift later thus causing the engine to rev. higher only when the engine is cold. This causes the engine to warm faster and pollute less. You may have noticed stiffer shifting in the lower gears, at least when your car is cold. The Vacuum Upshift Circuit is located on the right side of the Tranny (facing forward). There is a hard green vacuum line (if it's stock) coming up from the right side and goes into the covered compartment just in front of the passenger windshield. Lift that cover and you will find the Vacuum Switch with a RUBBER hose adapting the switch to the Hard Green Vacuum line. There should be another smaller Black/Wht. stripe Vacuum line coming out of the top of the Switch that goes to a Vacuum Manifold under the Dash. Make sure the hoses are good and still connected. If that end is good, the other end at the Tranny and inbetween needs to be checked next. Beyond that the Black/Wht. stripe hose that goes to the Vacuum Manifold could be checked for Vacuum present and the switch checked to see if it's functioning.

Probably more information than you wanted to know:eek:

Good Luck!:thumbsup:

C as in 220

P.S. Welcome to the Forum!:)
 
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