1984 Buick Electra Code 21 TPS

1984 BUICK ELECTRA
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MER041352
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  • 3 POSTS
I have a 1984 Buick with CCC emission control. I am getting a code of 21 (high voltage on throttle position sensor input). I have connected an ohmmeter to the sensor and cycled it through the full range of motion. The ohmmeter tracks the sensor without gaps. Why would I get this code and where should I look for problems in the circuit? What resistance readings should I look for?

Also: I have a sensor I cannot identify. It is in the intake manifold and the connector is a coaxial type instead of two pins. The connector has rotted, but I cannot find a replacement connector or even a listing for such a part. What is this sensor?
Jun 1, 2006 at 12:51 AM
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LOSONE
  • ✓Experienced Mechanic
  • 1,616 POSTS
You don't test it with an ohm meter. The center pin should read .5 volts with the key on engine off. It is adjustable. Loosen the screws and adjuct the TPS to read .5 volts with the choke off. If it won't adjust replace it and then set it. Good luck
Jun 1, 2006 at 8:43 AM
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Suggested Repair

Do not test the throttle position sensor with an ohmmeter. With the key on and engine off, and the choke off, the center pin should read 0.5 volts. Loosen the screws and adjust the sensor to that reading. If it will not adjust, replace the sensor and then set it.

Conversation Summary

The owner of a 1984 Buick Electra Estate Wagon with CCC emission controls reported code 21, high voltage on the throttle position sensor input. An ohmmeter sweep showed the sensor resistance changing smoothly through its range. The expert said the sensor should be checked with a voltmeter instead: the center pin should read 0.5 volts with the key on, engine off, and choke off, and it is adjustable. If it cannot be adjusted, replace it and then set the voltage. The unidentified coaxial intake-manifold sensor was not identified in the replies.

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