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DTC P0121-A: TPS VOLTAGE DOES NOT AGREE WITH MAP Chrysler LHS II

Testing & Diagnostics ~727 words

Note. For connector terminal ID, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article.

  1. Using scan tool, read Diagnostic Trouble Codes (DTCs). If a MAP sensor DTC is present, perform appropriate test. See «DTC MESSAGES & CODES»(ref-576-S35197105972000030800000) table. If no MAP sensor DTC is present, go to next step.
  2. Using scan tool, read MAP sensor voltage. If MAP sensor voltage is 3.5 volts or more, go to next step. If MAP sensor voltage is less than 3.5 volts, go to «TEST NTC-8A: CHECKING MAP SENSOR CALIBRATION»(ref-576-S00862455302000030800000)
  3. Start engine. Using scan tool, read MAP sensor voltage. If MAP sensor voltage dropped from more than 3.5 volts to less than 2 volts, go to next step. If MAP sensor did not drop from more than 3.5 volts to less than 2 volts, go to «TEST NTC-8A: CHECKING MAP SENSOR CALIBRATION»(ref-576-S00862455302000030800000) .
  4. TPS VOLTAGE DOES NOT AGREE WITH MAP sets when Powertrain Control Module (PCM) performs 2 different tests on Throttle Position (TP) sensor. Tests performed are a high voltage test and a low voltage test. The high voltage test is performed when engine speed is low and manifold vacuum is high. These conditions indicate throttle plate is nearly closed. With throttle plate nearly closed, TP sensor signal voltage output must be low. Go to next step.
  5. The low voltage test is performed when vehicle speed is more than 25 MPH and manifold vacuum is low. These conditions indicate throttle plate is open. With vehicle speed more than 25 MPH and throttle plate open, TP sensor signal voltage must be high. If proper TP sensor signal voltage is not present for either high voltage test or low voltage test, this trouble code will set after 4 continuous seconds. Go to next step.
  6. Possible causes are: failed PCM, TP sensor failure, engine mechanical failure, connector or wiring harness problem, malfunctioning Vehicle Speed Sensor (VSS) or malfunctioning MAP sensor. Go to next step.
  7. Check throttle plate and linkage for binding. Ensure throttle linkage is at idle position. Repair either condition as required. Perform «TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES»(ref-576-S36272092702000030800000) . If both conditions are okay, go to next step.
  8. If TP sensor ground circuit and 5-volt supply circuit are switched, this trouble code will set. Disconnect TP sensor connector. Inspect TP sensor connector for correct wire placement and damage. If TP sensor connector wire placement is incorrect or damaged, repair as necessary. Perform «TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES»(ref-576-S36272092702000030800000) . If TP sensor connector wire placement is correct and not damaged, go to next step.
  9. Using a voltmeter, check voltage on TP sensor connector 5-volt supply circuit. See «TP SENSOR CONNECTOR WIRE IDENTIFICATION»(ref-576-S40977155302000030800000) table. If voltage is 5 volts or more, go to next step. If voltage is less than 5 volts, repair open 5-volt supply circuit. Perform «TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES»(ref-576-S36272092702000030800000) .
  10. Reconnect TP sensor connector. Turn ignition on with engine off. Using scan tool, read TP sensor voltage. If TP sensor voltage is one volt or less, go to next step. If TP sensor voltage is more than one volts, replace TP sensor. Perform «TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES»(ref-576-S36272092702000030800000) .
  11. While observing scan tool, slowly open and close throttle. If voltage change is smooth, go to next step. If voltage change is not smooth, replace TP sensor. Perform «TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES»(ref-576-S36272092702000030800000) .
  12. While observing scan tool, open throttle to Wide Open Throttle (WOT) position. If TP sensor voltage is more than 3.5 volts at WOT, go to next step. If TP sensor voltage is 3.5 volts or less at WOT, replace TP sensor. Perform «TEST VER-2A: ROAD TEST VERIFICATION»(ref-576-S36272092702000030800000) .
  13. While monitoring scan tool display, wiggle wiring harness between TP sensor and PCM. If voltage does not change at any time, go to next step. If voltage changes at any time, repair wiring harness as necessary where wiggling caused problem to appear. Perform «TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES»(ref-576-S36272092702000030800000) .
  14. Using scan tool, read FREEZE FRAME data. Ensure hex code matches DTC on scan tool. Hex code should be 84. Use this information for additional diagnostics. See «INACTIVE TROUBLE CODE CONDITION»(ref-576-S27765318282000030800000) under SELF-DIAGNOSTICS. Test is complete. Perform «TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES»(ref-576-S36272092702000030800000) .
ApplicationWire Color
TP Sensor Signal CircuitOrange/Dark Blue
TP Sensor 5-Volt Supply CircuitViolet/White
TP Sensor Ground CircuitBlack/Light Blue

TP SENSOR CONNECTOR WIRE IDENTIFICATION

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