Circuit Description
A dash light is illuminated by the PCM if the diagnostics has detected certain errors related to the Accelerator Pedal Position (APP) sensor. When the PCM is commanding the Service Throttle Soon Lamp ON, the voltage potential of the circuit will be low (near 0 volts). When the PCM is commanding the Service Throttle Soon Lamp OFF, the voltage potential of the circuit will be high (near battery volts). The primary function of the PCM in this circuit is to supply the ground for the Service Throttle Soon Lamp. This is a type D DTC.
Conditions for Setting the DTC
| • | Service Throttle Soon lamp requested ON. |
| • | Voltage on the Service Throttle Soon control circuit high (near battery volts). |
or
| • | Service Throttle Soon lamp requested OFF. |
| • | Voltage on the Service Throttle Soon control circuit low (near 0 volts). |
Action Taken When the DTC Sets
Will not turn ON the MIL.
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL off after three consecutive trips without a fault condition. |
| • | A History DTC will clear when forty consecutive warm-up cycles that the diagnostic does not fail (coolant temperature has risen 5°C (40°F) from start up coolant temperature and engine coolant temperature exceeds 71°C (160°F) that same ignition cycle. |
| • | Use of a Scan Tool |
Diagnostic Aids
A faulty bulb or the control circuit shorted to ground will cause a P1654 to set.
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
-
Be sure that both the ON and the OFF states are commanded. Repeat the commands as many times as necessary.
-
If no trouble is found in the control circuit or the connections at the PCM, the PCM maybe malfunctioning, however, this is an extremely unlikely failure.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 |
Important: Before clearing DTCs use the scan tool to record freeze frame and failure records for reference, as data will be lost when Clear Info function is used. Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||
Does the lamp turn ON and OFF with each command? | -- | |||||||||
3 | DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids. If additional DTCs were stored refer to those table(s). Are any additional DTCs stored? | -- | Go to the Applicable DTC table | Go to Diagnostic Aids | ||||||
4 |
Is the lamp OFF? | -- | ||||||||
5 | With a fused jumper wire connected to ground, probe the lamp control circuit in the PCM harness connector. Is the lamp ON?. | -- | ||||||||
6 |
Was a repair performed? | -- | ||||||||
7 | Service Throttle Soon lamp control circuit is shorted to ground, repair as necessary. Is the action complete? | -- | -- | |||||||
8 |
Is the repair complete? | -- | -- | |||||||
Replace the PCM. Important: The new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | ||||||||
10 |
Does the Scan Tool indicate that the diagnostic Passed? | -- | ||||||||
11 | Using the Scan Tool, select Capture Info, Review Info. Are any DTCs displayed that have not been diagnosed? | -- | Go to the Applicable DTC Table | System OK |
