DTC 2-3-1

EM. Diagnostic trouble codes (DTCs) 2-3-1 and 2-3-2 MFI LH 2.4

* 2-3-1 Adaptive fuel trim too lean or too rich at part loads

If DTC 2-3-1 Is logged at the same time as other DTCs, the first code to be presented by the OBD system should be remedied first. The following DTCs are regarded as secondary faults.

DTC conditions
The adaptive system has compensated for gradual changes in the fuel/air mixture. The control module receives information from the HO2S if the fuel/air mixture is too rich or too lean at part loads. The adaptive system compensates for this by enriching or weakening the mixture in order to maintain lambda=1, which is the correct fuel/air mixture. When the adaptive system has almost compensated as much as it can this is Interpreted as abnormal and DTC 2-3-1 Is logged.

Causes of fault:
1. The mixture is too lean: 2. The mixture is too rich:
Air leaks. High fuel pressure.
Low fuel pressure. Contaminated engine oil.
Faulty sensor signals Leaking injectors.
Leaking (EVAP) valve.
Faulty sensor signals.
Leak in exhaust system.

Fault symptoms:
Engine stops running when being started from cold.
High fuel consumption.
Various driving problems.


* 2-3-2 Adaptive fuel trim too lean or too rich at idling

If DTC 2-3-2 Is logged at the same time as other DTCs, the first code to be presented by the OBD system should be remedied first. The following DTCs are regarded as secondary faults.

DTC conditions
The adaptive system has compensated for rapid changes in the fuel/air mixture. The control module receives information from the HO2S it the fuel/air mixture is too rich or too lean in the idling range. The adaptive system compensates for this by enriching or weakening in order to maintain lambda=1, which is the correct fuel/air mixture. When the adaptive system has almost compensated as much as it can this Is interpreted as abnormal and DTC 2-3-2 is logged.

Causes of fault and fault symptoms:
See above.


EM1




Connecting the CO meter
- Start the engine and let it warm up.

Warning! The CO terminal may be very hot.

- Connect the CO meter with adaptor 5410 to the CO output on the TWO.
- Disconnect the HO2S 1-pole connector.
^ Continue with Resetting adaption EM2.

EM2




Resetting adaption
- Remove fuse 1 (or 31).
- Install fuse 1 (or 31).
^ Checking the Basic CO and HO readings EM3.

EM3




Checking the basic CO and HC readings

Note: Take a reading from the CO meter within 30 seconds of the engine being started

Adaption starts compensating for faults as soon as the engine is started.
- Start the engine.
- Take the basic CO and HC readings.
CO content should be 0.4-0.8 %.
HC content should be below 400 ppm.

If the basic CO and HC readings are OK:
^ Connect the test box EM8.
Carefully check input signals for contact resistance.

If the HC reading is too high:
^ Check the ignition coil, Ignition leads, rotor and spark plugs.

If the basic CO reading is too high:
The mixture is too rich.
^ Basic CO reading too high EM4.

If the basic CO reading is too low:
The mixture is too lean.
^ Basic CO reading too low EM7.

EM4




Basic CO reading too high
- Warm up the engine.
- Disconnect and plug the crankcase ventilation.
- Read off the CO content.

If the CO content decreases to 0.4-0.8 %:
The engine oil is contaminated with fuel.
^ Change the engine oil.
^ Change the oil filter.

If the CO content is still high:
^ Check the fuel pressure EM5.

EM5




Checking the fuel pressure
- Connect the 1-pole connector.
Check the fuel pressure and residual pressure in accordance with X. Fuel pressure and residual pressure X. Fuel Pressure and Residual Pressure

If fuel pressure and residual pressure are OK:
^ Check the EVAP system EM6.

EM6




Check Evaporative Emission (EVAP) system.
^ Check the EVAP system in accordance with Y. Checking the EVAP system. Y. Checking the Evaporative Emission (EVAP) System

If the EVAP system is OK:
^ Connect the test box EM8.

EM7




Basic CO reading too low
- Connect the 1-pole connector.
^ Z. Checking the air and vacuum hoses Z. Checking the Air and Vacuum Hoses

If the air and vacuum hoses are OK:
^ Check the exhaust system EM8.

If the air and vacuum hoses are defective:
^ Remedy as necessary.

EM8




Checking the exhaust system
^ Check the exhaust system in accordance with BE. Mechanical overview BE. Mechanical Overview

If the exhaust system is OK:
^ X. Fuel pressure and residual pressure. X. Fuel Pressure and Residual Pressure
If the fuel pressure and residual pressure are OK, continue with Connecting the test box EM9.

If the exhaust system is leaking:
^ Remedy as necessary.

EM9




Connecting the test box
Connect the test box to MFI and check the GND points in accordance with P1-P2. P. Test Box, Signal Description
^ Continue with Checking the input and output signals EM10.

EM10




Checking the input and output signals
- Connect the control module to the test box.
- Install fuse 1 (or 31).
Take readings with the ignition on and the engine idling.
Check the following signals and compare them with the values in PB. Signal description MFI LH 2.4. PB. Signal Description MFI LH 2.4
^ GND MAF sensor #6.
^ MAF signal sensor #7.
^ ECT sensor #13.

If readings are abnormal check the wiring and connections for contact resistance in accordance with NA6 and clean connectors and treat them for corrosion in accordance with NA7. NA. Checking the Wiring