DTC P1290: ELECTRIC THROTTLE CONTROL FORCED IDLE MODE
Acceleration Position Sensor (APS) circuit provides a voltage signal relative to acceleration pedal angle. AP1 angle will vary about 13 percent at idle position to about 87 percent at Wide Open Throttle (WOT). Code detects if system is in Electric Throttle Control (ETC) Forced Idle Mode (Fail Safe Mode). Condition for setting DTC:
Ignition is on.
Forced Idle Mode is active.
An intermittent may be caused by poor connections, misrouted harness, rubbed through wire insulation or broken wire inside insulation. Check for poor connection at PCM, backed out terminals, improper mating, broken lock, improperly formed or damaged terminals and poor terminal to wire connection. Using scan tool, monitor APS1, 2 and 3. While moving wire harnesses and connectors, a change in display will indicate location of fault. If DTC P1290 cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.
1. Perform ON-BOARD DIAGNOSTIC II SYSTEM CHECK. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. Perform ELECTRIC THROTTLE CONTROL SYSTEM CHECK. If no problems are present, go to next step.
3. Using scan tool, observe APS angle reading while slowly opening throttle valve. APS1 angle increases from 12-14 percent at idle to 85-89 percent at WOT. Readings should change steadily and evenly. If APS do not operate as specified, go to next step. If APS operate as specified, see DIAGNOSTIC AIDS.
4. Disconnect APS1, 2, and 3 and observe readings on scan tool. If APS1 reading is zero volts, go to next step. If APS1 reading is not as specified, go to step 6.
5. Connect test light between 5-volt supply circuits and APS signal circuits at APS1, 2 and 3 harness connectors. If APS readings are about 5 volts, go to step 7. If APS readings are not about 5 volts, go to step 8.
6. Check APS1, 2 and 3 signal circuits for shorts to voltage. Check APS1, 2 and 3 ground circuits for high resistance between PCM and AP ensors. Check APS1, 2 and 3 ground circuits for poor connections. If problem is present, repair as necessary and retest system. If problem is not present, go to step 9.
7. Check APS1, 2 and 3 signal circuits or 5-volt supply circuits for poor connections. Check APS1, 2 and 3 signal circuits or 5-volt supply circuits for high resistance between PCM and AP sensors. If problem is present, repair as necessary and retest system. If problem is not present, go to step 9.
8. Replace faulty AP sensor. Retest system.
9. Replace and reprogram PCM. Retest system.
Sunday, December 30th, 2012 AT 7:58 PM