DTC 1-2-1 Temp. Sensor Interval Too Short

Conditions for DTC:
- ECT sensor signal period less than 2.4 ms for at least 1 second.

Sources of fault:
- Fault in engine management system.
- Loose contact.

Symptoms:
- Engine temperature gauge sticking at minimum. Check ECT signal, below.

Checking ECT Signal:





- Ignition off.
- Expose instrument panel. (Remove Dash Board Cover) Service and Repair
- Connect test box to cable harness connector and check ground points. Connecting Test (Breakout) Box

Test Box On Dashboard/Cable Harness Dashboard:

- Connect test box between instrument panel and cable harness connector.
- Ignition on.





- Connect a frequency counter across test box terminals # 26 (# A26) and #15 (# A15).
- Frequency counter should read approximately:
50 Hz with engine cold (engine temperature 20 °C/68 °F)
25 Hz with engine warm (engine temperature 80 °C/176 °F).

If reading is correct:
- Loose contact in lead between instrument panel connector # A26 and engine management unit connector # B23.
- Check lead and connections for loose contact. Checking Cables and Terminals

If reading is incorrect:
- Fault in engine management system. Follow fault tracing instructions in appropriate ALLDATA powertrain Management section.