Code 57

  • 1991 FORD RANGER
  • 2.3L
  • 4 CYL
  • 2WD
  • 121,000 MILES
Going up hills or mountain 65 to 75 mph loses power horrible vibration feels like blowing up. Down shifted to third cleared up. But next mountain same thing even. A lot of backfiring and no power at all. Finally get to top smoothed our ran fine. Now now power on small hills. Pulled code got code 57?
Thursday, February 14th, 2019 AT 10:15 AM

1 Reply

  • 108,154 POSTS
Hi and thanks for using 2CarPros.

The code is related to the throttle position sensor. The power readings are too low when the computer does a self test.

Picture 1 below shows the possible causes. Take a look through that first. If you find the sensor is bad, here are the directions for replacement. Picture 2 correlates with these directions.

Throttle Body And Related Components
Picture 2

1. Disconnect the Idle Speed Control By-Pass Air (ISC-BPA) valve assembly connector from the wiring harness.
2. Remove the two ISC-BPA retaining bolts.
3. Remove the ISC-BPA valve and gasket.
4. Disconnect the Throttle Position (TP) sensor electrical connector.
5. Remove the two TP sensor retaining bolts, TP sensor, and gasket.
6. Position the TP sensor and gasket on the throttle body. Make sure that the rotary tangs on the TP sensor are aligned with the throttle body.
CAUTION: Slide rotary tangs into position over the throttle shaft blade, then rotate the TP sensor CLOCKWISE to the installed position. Failure to install the TP sensor in this manner may result in excessive idle speeds.
7. Install the two TP sensor retaining bolts, torquing to 25-33 lb. in. (2.8-3.8 N-m).
8. Clean the ISC-BPA gasket mating surfaces.
NOTE: If scraping is necessary, use care not to damage ISC-BPA valve or throttle body gasket surfaces, or drop material into the throttle body.
9. Install the gasket and ISC-BPA valve on the throttle body.
10. Install the ISC-BPA retaining screws, torquing them to 71-102 lb. in. (8-11 N-m).
11. Connect the electrical connectors for the ISC-BPA valve and the TP sensor.
NOTE: The TP sensor is not adjustable.

Here is a link that discusses backfires, so take a look through it too. You may find it helpful.

Let me know if this helps or if you have other questions.

Take care,
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Thursday, February 14th, 2019 AT 7:46 PM

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