DTC 4-1-1

4-1-1 THROTTLE POSITION SENSOR SIGNAL

Preconditions for DTC
^ If the ECM receives a signal from the Throttle Position (TP) Sensor which corresponds to a throttle angle less than 3.3° (0.1 Volts) (signal too low) or higher than 100.1° (4.9 Volts) (signal too high), the ECM interprets this as a fault and DTC 4-1-1 is set.


Substitute values
^ Idle Air Control (IAC) Valve inhibited.
^ Throttle angle set at 32.2°.
^ The ECM uses the Mass Air Flow (MAF) signal to determine idling position.
^ The ECM uses the Mass Air Flow (MAF) signal and RPM to determine full-load position.

Fault sources
^ Signal too high:
- Voltage or signal lead short circuited to voltage supply.
- Break in signal or ground lead.
- Contact resistance in connectors.
- Defective TP sensor.

^ Signal too low:
- Voltage or signal lead short circuited to ground.
- Break in voltage lead.
- Contact resistance in connectors.
- Defective TP sensor.

Fault symptoms
^ Car feels a bit sluggish.
^ High idling speed in neutral.

TESTING PROCEDURE





Other DTCs
^ Read off other DTCs.

If DTC 1-2-3, 1-1-2, 3-1-4 and possibly 4-1-3 are stored:
- Check the Throttle Position (TP) Sensor's, Engine Coolant Temperature (ECT) Sensor's, Camshaft Position (CMP) Sensor's and EGR temperature Sensor's joint connector A18 on the ECM for signs of contact resistance, oxidation and disruption.
If none of the above DTCs is stored:
- Check Status message.





Status Message
^ Check current status message.

If Status message is: Permanent fault, signal too high:
- Proceed to: PERMANENT FAULT, SIGNAL TOO HIGH section below.
If Status message is: Permanent fault, signal too low:
- Proceed to: PERMANENT FAULT, SIGNAL TOO LOW section below.
If Status message is: Intermittent fault, signal too high:
- Proceed to: INTERMITTENT FAULT, SIGNAL TOO HIGH section below.
If Status message is: Intermittent fault, signal too low:
- Proceed to: INTERMITTENT FAULT, SIGNAL TOO LOW section below.

PERMANENT FAULT, SIGNAL TOO HIGH





Checking the Ground Lead
^ Switch Ignition OFF.
^ Wait for approx. 150 seconds.
^ Disconnect the TP sensor.

NOTE: If the engine cooling fan continues operating after engine Switch-OFF, it must be allowed to finish before resistance measurements are taken.

^ Connect an ohmmeter between TP sensor connector 1 and ground.

The ohmmeter should show approx. 0 ohms.

If the reading is OK:
- Check the voltage lead.
If the reading is incorrect:
- Check the ECM connector.





Checking the ECM Connector
^ Switch Ignition OFF.
^ TP sensor disconnected.
^ Rectify the ECM connector with regard to contact resistance and oxidation.
^ The ECM connected.





^ Connect an ohmmeter between TP sensor connector 1 and ground.

The ohmmeter should show approx. 0 ohms.

If the reading is OK:
- The source of the DTC is poor contact in the ECM connector.
If the reading is incorrect:
- Check the lead between TP sensor connector 1 and ECM A18 for signs of a break.





Checking the Voltage Lead
^ Switch Ignition ON.
^ TP sensor disconnected.
^ Connect a voltmeter between the TP sensor's connector 2 and ground.

The voltmeter should show approx. 5 Volts.

If the reading is OK:
- Check the signal lead.
If the value differs:
- Check the lead between the TP sensor connector 2 and control module A15 for signs of a short circuit to voltage supply.





Checking the Signal Lead
^ Switch Ignition ON.
^ TP sensor disconnected.
^ Connect a voltmeter between the TP sensor connector 3 and ground.

The voltmeter should show approx. 5 Volts.

If the reading is OK:
- Check the TP sensor signal.
If the voltmeter shows approx. 0 Volts:
- Check the ECM connector.
If the voltmeter shows more than approx. 5 Volts:
- Check the lead between TP sensor connector 3 and ECM A16 for signs of short circuiting to voltage supply.
- After rectification: Check the TP sensor.





Checking the ECM Connector
^ Switch Ignition OFF.
^ TP sensor disconnected.
^ Rectify the ECM connector with regard to contact resistance and oxidation.
^ ECM connected.
^ Switch Ignition ON.





^ Connect a voltmeter between TP sensors connector 3 and ground.

The voltmeter should show approx. 5 Volts.

If the reading is OK:
- The source of the DTC is poor contact in the ECM's connector.
If the reading is incorrect:
- Check the lead between TP sensor connector 3 and the ECM A16 for signs of a break.





Checking the TP Sensor Signal
^ Switch Ignition OFF.
^ Connect the TP sensor.
^ START the engine and let it run at idling speed.
^ Look up the DTC parameter list.





^ Read off the throttle angle.

Throttle angle should be 3 - 8° when the engine is at idling speed, increasing as the accelerator pedal is pressed down.

If the reading is OK:
- The source of the DTC is poor contact in the TP sensor's connector. Rectify the connector with regard to contact resistance and oxidation.
If the reading is incorrect:
- Test with a new TP sensor.





Checking the TP Sensor
^ The TP sensor may break as a sequential fault resulting from short circuiting of the signal lead to voltage supply.
^ Check the TP sensor as below.
^ Switch Ignition OFF.
^ Connect the TP sensor.
^ START the engine and let it run at idling speed.
^ Look up the DTC parameter list.





^ Read off the throttle angle.

Throttle angle should be 3 - 8° when the engine is idling, increasing as the accelerator pedal is pressed down.

If the reading is OK:
- TP sensor is OK.
If the reading is incorrect:
- Test with a new TP sensor.

PERMANENT FAULT, SIGNAL TOO LOW





Checking the Voltage Lead
^ Switch Ignition OFF.
^ Wait for approx. 150 seconds.
^ Disconnect the TP sensor.

NOTE: Any fan overspin must be completed before resistance measurement can be done.

^ Connect an ohmmeter between TP sensor connector 2 and ground.

The ohmmeter should show 0.4 - 0.6K ohms.

If the reading is OK:
- Check the signal lead.
If the ohmmeter shows Infinite resistance:
- Check the ECM connector.
If the ohmmeter shows approx. 0 ohms:
- Check the lead between the TP sensor connector 2 and control module A15 for signs of short circuiting to ground.





Checking the ECM Connector
^ Switch Ignition OFF.
^ TP sensor disconnected.
^ Rectify the ECM connector with regard to contact resistance and oxidation.
^ ECM connected.
^ Switch Ignition ON.





^ Connect a voltmeter between the TP sensor connector 2 and ground.

The voltmeter should show approx. 5 Volts.

If the reading is OK:
- The source of the DTC is poor contact in the ECM's connector.
If the reading is incorrect:
- Check the lead between TP sensor connector 2 and ECM A15 for signs of a break.





Checking the Signal Lead
^ Switch Ignition ON.
^ TP sensor disconnected.
^ Connect a voltmeter between TP sensor connector 3 and ground.

The voltmeter should show approx. 5 Volts.

If the reading is OK:
- Check the TP sensor signal.
If the reading is incorrect:
- Check the lead between TP sensor connector 3 and ECM A16 for signs of short circuiting to ground.





Checking the TP Sensor Signal
^ Switch Ignition OFF.
^ Connect the TP sensor.
^ START the engine.
^ Look up the DTC parameter list.





^ Read off the throttle angle.

Throttle angle should be 3 - 8° when the engine is at idling speed, increasing as the accelerator pedal is pressed down.

If the reading is OK:
- The source of the DTC is poor contact in the TP sensor's connector. Rectify the connector with regard to contact resistance and oxidation.
If the reading is incorrect:
- Test with a new TP sensor.

INTERMITTENT FAULT, SIGNAL TOO HIGH





Checking the Voltage Lead
^ Switch Ignition OFF.
^ Disconnect the TP sensor.
^ Switch Ignition ON.
^ Connect a voltmeter between the TP sensor's connector 2 and ground

The voltmeter should show approx. 5 Volts.

If the reading is OK:
- Check the leads and connectors.
If the reading is different:
- Check the lead between the TP sensor's connector 2 and control module A15 for signs of short circuiting to voltage supply.





Checking the Leads and Connections
^ Check the TP sensor's and ECM's connectors for signs of loose connection, contact resistance and oxidation.
^ Check the lead between TP sensor connector 3 and ECM A16 for signs of an intermittent break as well as intermittent short circuiting to voltage supply.
^ Check the lead between TP sensor connector 1 and ECM A18 for signs of an intermittent break.

INTERMITTENT FAULT, SIGNAL TOO LOW

Checking the Leads and Connections
^ Check the TP sensor's and ECM's connectors for signs of loose connection as well as contact resistance and oxidation.
^ Check the lead between TP sensor connector 3 and ECM A16 for signs of intermittent short circuiting to ground.
^ Check the lead between TP sensor connector 2 and ECM A15 for signs of an intermittent break, and intermittent short circuiting to ground.