Code 17

THROTTLE POSITION SENSOR CIRCUIT - DTC 17

The ECM looks for the throttle position sensor signal voltage below the low limit for idle recognition.

The throttle position sensor has two tracks; one for engine management and one for transmission control. The ECM monitors the EMS track. The sensor is connected to the throttle valve shaft so that increased throttle opening results in higher voltage. Normal signal voltage at idle is 0.6 volt; normal signal voltage at full throttle is approximately 4.5 volts.

The throttle position sensor signal is used by the ECM for the control of a number of functions:
- Idle speed control
- Ignition idle strategy selection
- Overrun fuel cutoff
- Adaptive idle fueling trim
- Main fuel metering strategy
- Main ignition strategy
- Acceleration enrichment
- Deceleration leaning
- Full load enrichment

NOTE: Other sensor inputs are also required for the above listed functions.

The ECM will flag DTC 17 if the signal voltage is less than 250 millivolts any time the ignition is ON.

Conditions Required for DTC 17 Flagging
Throttle position sensor voltage signal to ECM: Less then 250 millivolts
Conditions monitored: Any time during ignition ON
Response time: 64 milliseconds

Limp Home Default
If DTC 17 is flagged, a fixed part-throttle voltage (1.5 V) is substituted for the missing input. The throttle position functions will not operate.

Possible Faults
- High resistance connection to ECM or throttle position sensor.
- Short circuit or open circuit wiring from the ECM to the throttle position sensor.
- Loose or incorrectly adjusted throttle position sensor Defective throttle position sensor (worn).

Diagnostic Notes
The EMS throttle position sensor signal voltage can be monitored and intermittent faults captured using the PDU "Datalogger" function.






NOTE: JDS displays only the transmission control track voltage.

Circuit Diagram

Circuit Diagram:

Flow Chart: DTC 17

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Flow Chart: DTC 17: