DTC 1-3-1

1-3-1 ENGINE SPEED SENSOR SIGNAL, ABSENT

Preconditions for DTC
^ If the control module does not receive a signal from the Engine Speed (RPM) Sensor for 20 revolutions of the engine, the ECM reads the Camshaft Position Sensor (CMP) and interprets this as a fault and sets DTC 1-3-1.

Substitute value
^ No fuel injection or ignition.

Fault sources
^ Break in signal or ground lead.
^ Signal lead short circuited to ground or voltage.
^ Contact resistance in connectors.
^ Defective RPM sensor.

Fault symptoms
^ Engine does not start.
^ Engine cuts out.

TESTING PROCEDURE





Status Message
^ Check current status message.

If Status message is: Permanent fault:
- Proceed to: PERMANENT FAULT section below.
If Status message is: Intermittent fault:
- Proceed to: INTERMITTENT FAULT section below.

PERMANENT FAULT





Checking the RPM Sensor's Resistance
^ Switch Ignition OFF.
^ Disconnect the RPM sensor.
^ Connect an ohmmeter between the RPM sensor's connector 1 and 2 (to RPM sensor).

The ohmmeter should show 200 - 500 ohms depending on the RPM sensor's temperature.

If reading is OK:
- Check the ground lead.
If reading is incorrect:
- Test with a new RPM sensor.





Checking the Ground Lead
^ Switch Ignition OFF.
^ Wait for approx. 150 seconds.
^ RPM sensor disconnected.
^ Connect an ohmmeter between the RPM sensor's coupling (to ECM) connector 1 (automatic transmission; connector 2) and ground.

The ohmmeter should show approx. 0 ohms.

If reading is OK:
- Check of signal lead resistance to ground.
If reading is incorrect:
- Check the ground lead's ground connectors.





Checking the Ground Lead's Ground Connectors
^ Switch Ignition OFF.
^ RPM sensor disconnected.
^ Rectify the ECM's connections and ground connectors 31/32 and 31/33 with regard to contact resistance and oxidation.





^ ECM connected.
^ Connect an ohmmeter between the RPM sensor's connector (to ECM) 1 (automatic transmission; connector 2) and ground.

The ohmmeter should show approx. 0 ohms.

If reading is OK:
- Check of signal lead resistance to ground.
If reading is incorrect:
- Check the lead between the RPM sensor connector 1 (automatic transmission; connector 2) and ECM A6 for signs of a break.





Check of signal Lead Resistance To Ground
^ Switch Ignition OFF.
^ RPM sensor disconnected.
^ Connect an ohmmeter between the RPM sensor's connector 1 and 2 (to ECM).

The ohmmeter should show 15 - 20K ohms.

If reading is OK:
- Check the signal lead's short circuit to voltage supply.
If the ohmmeter shows approx. 0 ohms:
- Check the lead between the RPM sensor connector 2 (automatic transmission; connector 1) and ECM A20 for signs of short circuiting to ground.
If ohmmeter shows infinite resistance:
- Check the ECM's connector.





Checking the ECM's Connector
^ Switch Ignition OFF.
^ RPM sensor disconnected.
^ Rectify the ECM connector with regard to contact resistance and oxidation.





^ ECM connected.
^ Connect an ohmmeter between the RPM sensor's connector 1 and 2 (to ECM).

The ohmmeter should show 15 - 20K ohms.

If reading is OK:
- Source of DTC is poor contact in ECM's connector.
If reading is incorrect:
- Check the lead between the RPM sensor connector 2 (automatic transmission; connector 1) and ECM A20 for signs of a break.





Checking the Signal Lead Short Circuit To Voltage Supply
^ Switch Ignition ON.
^ RPM sensor disconnected.
^ Connect a voltmeter between RPM sensor connector 1 and 2 (to ECM).

The voltmeter should show 1 - 2 Volts.

If reading is OK:
- Check the RPM sensor's connector.
If reading is incorrect:
- Check the lead between the RPM sensor and connector 2 (automatic transmission; connector 1) and ECM A20 for signs of short circuit to voltage supply.





Checking the RPM Sensor's Connector
^ Switch Ignition OFF.
^ Rectify the RPM sensor's connector with regard to contact resistance and oxidation.





^ Try to START the engine.

If the engine STARTS:
- The reason the engine did not start was poor contact in the RPM sensor's connector and/or the ECM's connector.
- Rectify the connectors with regard to contact resistance and oxidation.
If the engine DOES NOT START:
- Check the connecting flange/flywheel for signs of damage and scratches through the RPM sensor's holes.
If no faults are detected on the connecting flange/flywheel:
- Test with a new RPM sensor.

INTERMITTENT FAULT





Checking the Leads And Connectors
^ Check the ECM's and RPM sensor's connector for signs of loose connection and contact resistance and oxidation.
^ Check the lead between the RPM sensor's connector 1 (automatic transmission; connector 2) and ECM A6 for signs of intermittent breaks.
^ Check the lead between the RPM sensor connector 2 (automatic transmission; connector 1) and ECM A2O for signs of intermittent short circuiting to voltage, intermittent short circuiting to ground and intermittent breaks.