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

When fault-tracing in the engine management system using DTM 3, DTC 1-2-2 is posted in the instrument panel's diagnostic system. So reset DTC to make sure it was not posted for that reason.





Conditions for DTC:
- ECT signal period longer than 62.25 ms.

Sources of fault:
- Signal lead short-circuited to battery supply.
- Signal lead short-circuited to ground.
- Open-circuit in signal lead.
- Fault in engine management system.

Symptoms:
- Engine temperature gauge sticks at minimum. Check Engine Management DTCs, see below.
- Intermittent fault, with temperature gauge reading minimum. Check leads and Connections, see below.

Checking DTCs, Engine Management System:





- Ignition on.
- Read off DTCs for engine management system, DLC A2.
- DTC 1-2-3 is the only one which affects the engine temperature gauge. It other DTCs come up, see appropriate ALLDATA section for fault-tracing procedures.

If DTC 1-2-3 has been posted:
- Fault in engine management system. See appropriate ALLDATA powertrain management section for fault-tracing procedures.

If DTC 1-2-3 has not been posted:
- Check signal lead to instrument panel, see below.

Check Signal Lead To Instrument Panel:





- 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 connectors.
- Ignition on.





- Connect a voltmeter across test box # 26 (# A26) and # 15 (# A15).
- Voltmeter should read approx. 5.5 V.

If reading is correct:
- Poor contacts in instrument panel connector.
- Check connector for loose contacts, contact resistance and oxidization. Checking Cables and Terminals

If voltmeter reads 0 V:
- Open-circuit or short-circuit to ground in signal lead between engine management system connector terminal # B23 and instrument panel terminal # A26. Check leads and connections for open-circuit and short-circuit to ground.
- In cars with ECC, also check signal lead between ECC control module terminal # A23 and instrument panel terminal # A26 for open-circuit and short-circuit to ground.
- Checking Cables and Terminals

If voltmeter reading equals battery voltage:
- Short-circuit to battery voltage in signal lead between engine management system connector terminal # B23 and instrument panel terminal # A26.
- Check leads and connections for short-circuit to battery supply.
- In cars with ECC, also check signal lead between ECC control module terminal # A23 and instrument panel terminal # A26 for short-circuit to battery supply/
- Checking Cables and Terminals

Checking Leads and Connections:





Check instrument panel connector A for loose contacts, contact resistance and oxidization. Check signal lead between instrument panel terminal # A26 and engine management system terminal # B23 for intermittent open-circuit, intermittent short-circuit to battery supply and short-circuit to ground. Checking Cables and Terminals