DTC 1-1-3

EB. Diagnostic trouble code (DTC) 1-1-3 MFI LH 2.4

* 1-1-3 Fuel trim too lean/rich

If DTC 1-1-3 is logged at the same time as other DTC's, 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 control module receives Information from the HO2S if the fuel/air mixture Is too rich or too weak. The control module's fuel trim circuit compensates for this by enriching or weakening the fuel/air mixture. When the control module has made a 25 % compensation (maximum upper or lower limit for the integrator) for 3 minutes, the situation is interpreted as abnormal and a DTC Is logged.

Causes of fault:
Grounding or short circuit in the H028 wiring.
Mixture very weak or rich.

Fault symptoms:
High fuel consumption.

EB1




Checking the 8lgnaI from the heated oxygen Sensor (HO2S)
- Start the engine.
Connect a voltmeter between terminal 1 (the 1-pole connector at the firewall) and GND.
The voltmeter should oscillate between 0.1 and 0.9 V.

If the voltmeter reads a fixed value between 0.1 V and 0.9 V:
^ Check the MAF sensor GND terminal EB2.

If this value is OK:
^ Check the MAF sensor GND terminal EB2.

If the voltmeter reads 0 V or more than 1.0 V:
^ Check the reference voltage EB10.

EB2




Checking the mass air flow (MAF) sensor GND terminal
- Switch off the engine.
- Disconnect the connector from the MAF sensor. Connect an ohmmeter between connector terminal 1 and GND.
The ohmmeter should read approx. 0 ohms.

If this value is OK:
^ Check the MAF sensor signal EB3.

If the reading is incorrect:
^ Check the GND terminal in the Intake manifold for resistance in accordance with NA6. NA. Checking the Wiring

EB3




Checking the mass air flow (MAF) sensor signal
- Clean the MAF sensor connector and treat it for corrosion in accordance with NA7. NA. Checking the Wiring
- Install the connector.
- Ignition on.
Connect a voltmeter between terminal 3 (on the back of the connector) and GND.
The voltmeter should read approx. 1.4 V.

If this value is OK:
The voltmeter showed a fixed value between 0.1 V and 0.9 V in EB1:
^ Continue with Resetting adaption EB4.

The voltmeter oscillated between 0.1 V and 0.9 V in EB1:
^ Continue with Connecting test box EB8.

If the reading is incorrect:
^ Try using a new MAF sensor.

EB4




Resetting adaption
- Warm up the engine.
- Switch off the engine.
- Remove fuse 1 (alt 31).
- Install the fuse.
Connect a voltmeter between the 1-pole HO2S connector and GND.
- Start the engine.
- Read the voltmeter and make a note of the reading.





Note: Read the voltmeter within 30 seconds of the engine being started.

Adaption starts to compensate for the fault as soon as the engine is started.

The voltmeter generally reads between 0.1 V and 0.5 V:
The mixture is weak.
^ Check the air and vacuum hoses EB6.

The voltmeter generally reads between 0.6 V and 0.9 V:
The mixture is rich.
^ Check the crankcase ventilation EB5.

EB5




Checking the crankcase ventilation
- Warm up the engine.
- Disconnect and plug the crankcase ventilation.
Connect a voltmeter between the HO2S 1-pole connector and GND (HO2S connected).
The voltmeter reading should start to fluctuate.

If the voltmeter reading starts to fluctuate:
The engine oil is contaminated with fuel.
^ Change engine oil and filter.

If the voltmeter still reads a high voltage (0.6 V - 0.9 V):
^ Check the fuel pressure and residual pressure EB7.

EB6




Checking the air and vacuum hoses
^ Z. Check the air and vacuum hoses. Z. Checking the Air and Vacuum Hoses

If air and vacuum hoses are OK:
^ Check that the exhaust manifold is not leaking in accordance with BE. BE. Mechanical Overview
^ Continue with Checking the fuel pressure and residual pressure EB7.

EB7




Checking the fuel pressure and residual pressure
^ X. Fuel pressure and residual pressure. X. Fuel Pressure and Residual Pressure

If fuel pressure and residual pressure are OK:
^ Connecting test box EB8.

EB8




Connecting test box
Connect test box to MFI LH 2.4 and check GND points in accordance with P1-P2. P. Test Box, Signal Description
^ Continue with Checking the output and input signals EB9.


EB9







Checking the output and input signals
- Connect the control module to the test box.
- Install fuse 1.
Take readings with the ignition on and the engine idling.
Check the following signals and compare them with the reference values in PB. Signal description MFI LH 2.4. PB. Signal Description MFI LH 2.4
^ GND MAF sensor #6.
^ Signal MAF sensor #7.
^ If values deviate, check connections for contact resistance in accordance with NA6. NA. Checking the Wiring

EB10




Checking the reference voltage
- Switch off the engine.
- Disconnect the 1-pole connector.
- Ignition on.
Connect a voltmeter between connector terminal 1 (to control module) and GND.
The voltmeter should read approx. 0.5 V.

If this value is OK:
^ Check the HO2S signal wiring for grounding in accordance with NA3. NA. Checking the Wiring
If the wiring is OK: Replace the H025.

If the reading is over 1 V:
^ Check the wiring between the connector and #24 on the control module connector for short circuits in accordance with NA4. NA. Checking the Wiring
^ Continue with Checking the HO2S EB12.

If the reading is 0 V:
^ Check the resistance of the wiring to GND EB11.

EB11




Checking the resistance of the wiring to GND
- Ignition off.
Connect an ohmmeter between the 1-pole connector (with the control module) and GND.
The ohmmeter should read infinite resistance.

If this value is OK:
^ Check the wiring for breaks in accordance with NA2. NA. Checking the Wiring

If the reading is 0 ohms:
^ Check the wiring for grounding in accordance with NA3. NA. Checking the Wiring

EB12




Checking the heated oxygen sensor (HO2S)
If the signal wiring has been short circuited it may be damaged.
- Remedy the fault and reconnect the HO2S.
- Reset adaption by removing fuse 1 (or 31).
- Install the fuse.
- Start the engine.
Connect a voltmeter between the 1-pole connector for the HO2S and GND.
The voltmeter reading should start to fluctuate after a while.

If the voltmeter mading fluctuates:
^ The HO2S is OK.

If the voltmeter reading does not fluctuate between 0.1 V and 0.9 V:
^ Try using a new HO2S.