Will not downshift

2001 CHEVROLET BLAZER
107,000 MILES • 4.3L • 6 CYL • 4WD • AUTOMATIC
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PHILIP CARDINALE
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SUV will not downshift. I had a complete tune up now wont downshift. the mechanic says it is not the transmission or TCM or PCM. what else could the problem be?
Nov 15, 2016 at 6:45 PM
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KOOLCADDY6
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Was your mechanic able to see if there is any codes in the system? Check the wiring on the TPS sensor or map/mass sensor. It is possible it may have got disconnected when he did the tune up. since it started after he did the tune up.
Nov 15, 2016 at 10:05 PM
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PHILIP CARDINALE
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Before he did the tune up it was bogging down. The plugs were shot and wires bad and it was running on only five cylinders. He did replace the four wheel drive control module before that. It is not throwing any codes. Any other ideas? thanks
Nov 16, 2016 at 7:39 AM
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MHPAUTOS
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A live data feed will see if the shift solenoids are actually working, you will have to get a quality scanner to see if you have live data read out on this model.
Nov 17, 2016 at 3:52 AM
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