DTC 1-3-1

1-3-1 ENGINE SPEED SENSOR SIGNAL




Trouble Code Conditions
If the Engine Control Module (ECM) does not receive a signal from the Engine Speed (RPM) Sensor for 40 crankshaft revolutions (estimated by the ECM using the Camshaft Position (CMP) Sensor signal), the ECM notes it as a fault and sets Diagnostic Trouble Code (DTC) 1-3-1.

Substitute value(s)
- No fuel injection or ignition.

Fault source(s)
- Signal lead short circuited to ground.
- Signal lead short circuited to live.
- Signal lead broken.
- Ground lead broken.
- Contact resistance in terminals.
- RPM sensor defect.

Fault symptom(s)
- Engine does not start.
- Engine stopped.

TEST PROCEDURE

CHECK ENGINE START
- Test engine start.

If engine does not start:
^ Permanent fault, signal absent. Proceed to: PERMANENT FAULT, SIGNAL ABSENT section below.

If engine starts:
^ Intermittent fault, signal absent. Proceed to: INTERMITTENT FAULT, SIGNAL ABSENT section below.




PERMANENT FAULT, SIGNAL ABSENT
Check RPM sensor resistance
- Ignition off.
- Disconnect RPM sensor.
- Connect an ohmmeter between terminal 1 and 2 on RPM sensor.

The ohmmeter should read approx. 240 ohms and max. 400 ohms with engine warm.

If value OK:
^ Check ground lead. Proceed to CHECK GROUND LEAD section below.

If value differs:
^ Test with new RPM sensor.




CHECK GROUND LEAD
- Ignition off.
- RPM sensor disconnected.
- Connect an ohmmeter between RPM sensor connector (to ECM) terminal 2 (automatic transmission: terminal 1) and ground.

The ohmmeter should read approx. 0 ohms.

If value OK:
^ Check signal leads short circuited to live. Proceed to CHECK SIGNAL LEADS SHORT CIRCUIT TO LIVE section below.

If value differs:
^ Check ECM connector. Proceed to CHECK ECM CONNECTOR section below.




CHECK ECM CONNECTOR
- Ignition off.
- RPM sensor disconnected.
- Check ECM connector for contact resistance and oxidation.
- ECM connected.



- Connect an ohmmeter between RPM sensor connector (to ECM) terminal 2 (automatic transmission: terminal 1) and ground.

The ohmmeter should read approx. 0 ohms.

If value OK:
^ Source of DTC is bad contact in ECM connector.

If value differs:
^ Check lead between RPM sensors terminal 2 (automatic transmission: terminal 1) and ECM # 48 for break.




CHECK SIGNAL LEADS SHORT CIRCUIT TO LIVE
- Ignition on.
- RPM sensor disconnected.
- Connect a voltmeter between RPM sensors connector terminal 1 (automatic transmission: terminal 2) and ground.

The voltmeter should read approx. 0 volts.

If value OK:
^ Check signal lead resistance. Proceed to CHECK SIGNAL LEAD RESISTANCE section below.

If value differs:
^ Check lead between RPM sensors terminal 1 (automatic transmission: terminal 2) and ECM # 47 for short circuit to live.




CHECK SIGNAL LEAD RESISTANCE
- Ignition off.
- RPM sensor disconnected.
- Connect an ohmmeter between RPM sensor connector terminal 1 (automatic transmission: terminal 2) and ground.

Ohmmeter should read 10 - 20 k ohms.

If value OK:
^ Check RPM sensor. Proceed to CHECK RPM SENSOR section below.

If ohmmeter reads approx. 0 ohms:
^ Check lead between RPM sensor terminal 1 (automatic transmission: terminal 2) and ECM # 47 for short circuit to ground.

If ohmmeter reads infinite resistance:
^ Check ECM connector. Proceed to CHECK ECM CONNECTOR section below.




CHECK ECM CONNECTOR
- Ignition off.
- RPM sensor disconnected.
- Check ECM connector for contact resistance and oxidation.
- ECM connected.



- Connect an ohmmeter between RPM sensor connector terminal 1 (automatic transmission: terminal 2) and ground.

The ohmmeter should read 10 - 20 k ohms.

If value OK:
^ Source of DTC is bad contact in ECM connector.

If value differs:
^ Check lead between RPM sensor terminal 1 (automatic transmission: terminal 2) and ECM # 47 for break.




CHECK RPM SENSOR
- Ignition off.
- Check RPM sensor connector for contact resistance and oxidation.
- Test engine start.

If engine starts:
^ Source of DTC is bad contact in RPM sensor connector. Check RPM sensor connector for contact resistance and oxidation.

If engine does not start:
^ Check carrier plate/flywheel for damage and RPM sensor aperture.
^ If no fault is detected in carrier plate/flywheel: Test with new RPM sensor.

NOTE: Check in Diagnostic Test Mode (DTM) 1 for automatic transmission whether DTC for RPM signal is triggered.




INTERMITTENT FAULT, SIGNAL ABSENT
Check leads and terminals
- Check ECM and RPM sensor connector for loose connection, as well as contact resistance and oxidation.
- Check lead between RPM sensor terminal 2 (automatic transmission: terminal 1) and ECM # 48 for intermittent break.
- Check lead between RPM sensor terminal 1 (automatic transmission: terminal 2) and ECM # 47 for intermittent short circuit to live, intermittent short circuit to ground, as well as intermittent break.