Diagnostic Aids

The "Scan" tester displays throttle position in volts. Closed throttle voltage should be less than 1.25 volts. TPS voltage should increase at a steady rate as throttle is moved to WOT. A Code 22 will result if circuits No. 416 and 417 are open or grounded. If Code 22 is intermittent, see INTERMITTENTS in TESTS W/O CODES article.

Fig 1: Code 22, Circuit Wiring Diagram

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code 22, Flow Chart

Courtesy of GENERAL MOTORS CORP.