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Cadillac Deville Code 70

Q. Hello. I have a 1990 Cadillac Deville that reads a code 70. That's an intermittent TPS signal. I replaced it yesterday. It helped a lot, but I still sputter a little on acceleration and get the 70 code. The engine just runs a little rough, but not in neutral or park. Have I done something wrong? Does it need adjusted? I did clear the codes because I had an e52 code after I unhooked the battery. That was cleared.

Cadillac Deville Code 70

Do you have any advice on this matter. It's a 4.9 liter with fuel injection. No anti-lock brakes. 87,000 miles and power steering.

Thanks a lot,

A. It must be a 1991 Deville since the 1990 Deville only had a 4.5 liter engine and no DTC 70. So that is the assumption I'm going to work on. DTC 70 is "Intermittent Throttle Position Sensor (TPS) signal".

The diagnostic test monitors Manifold Pressure (MAP) and Throttle Angle (TPS). If the MAP remains constant and there is a large change in TPS, the code will set. Engine operation requires that, any large change in Throttle Angle (TPS) must be followed by a change in Manifold Pressure (MAP).

So you solved the problem by replacing the TPS but it does need to be adjusted. Here is the procedure:

  1. Using a T-25 L-shape torx wrench, loosen the TPS screws just enough to permit the sensor to be rotated. Open the throttle and let it snap shut against the minimum air screw.
  2. Adjust the TPS so the voltage is 0.475 to 0.525 volts. Tighten the TPS mounting screws with the sensor in the adjusted position.
  3. Recheck the parameter to be sure the TPS voltage is 0.475 to 0.525 volts.

Once you make the adjustment it should smooth out.

Additional Information provided courtesy of ALLDATA

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© 2005 Vincent T. Ciulla

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