The
OBD
system:
OBD
stands for "On Board Diagnostics".
Many of the LH2.4 cars have a test-socket from which you can read the fault-codes of the
ECU
, EZK and TCU. The later model cars (1995-1998 940) has a serial interface instead of a test socket in which the VST-tool or an
OBDII
reader is supposed to plug in to read the fault-codes.
The LH2.4
ECU
costantly monitors the following things:
-The control module's own, internal functions.
-Heated oxygen sensor (HO2S) and fuel trim.
-Engine coolant temperature sensor.
-Mass air flow (
MAF
) sensor.
-Battery voltage.
-Throttle position switch (TP switch).
-Engine speed (RPM) signal from the engine control module (
ECM
).
-Speedometer signal.
-Knock enrichment signal from the ignition system (does not apply to B 230 F, B 204 FT/GT).
-The idle air control (IAC) valve.
A fault in any of these functions is presented as a diagnostic trouble code (DTC) in diagnostic test mode (DTM) 1.
The EZK116 constantly monitors the following things:
-The control module's own, internal functions.
-Knock sensor (KS) signal.
-Fuel system load signal.
-Timing pick-up signal.
-Temperature sensor signal.
-Signal from the EGR converter.
-Signal from the EGR temperature sensor.
A fault in any of these functions is presented as a diagnostic trouble code (DTC) in test function 1.
All the diagnostic trouble codes (DTCs) are reversible. This means that if a signal has resulted in a diagnostic trouble code (DTC) being stored and it is OK next time the ignition is turned on, the control module will use the programmed correct value instead of remaining in “limp-home” mode. But the diagnostic trouble code (DTC) remains stored in the memory.
Diagnostic Test Mode 1: Fault Code Retrieval.
* Place the cable into socket 2 (LH2.4 fuel injection test) or 6 (EZK116 ignition test).
* Turn the ignition ON to KPII without starting the engine.
* Select Mode 1 by pressing the button once and holding for more than 1 second but less than 3 seconds.
* The LED lamp will flash in successive series of three digits followed by a three-second pause. If there are no fault codes stored, it will flash 1-1-1 indicating the fuel injection system is operating correctly.
* Count the successive flashes and record the fault code.
* Press the button again.
* Record the fault code. If it is the same as the previous one, then no additional codes are stored. Repeat until all the codes stored are retrieved (maximum of three). If the car is from California you can read up to 17 fault-codes at the same time.
* Refer to the tables below for the interpretation of fault codes from the LH2.4 Fuel injection System and EZK 116 Ignition System.
* Move the cable into socket 6 (for ignition codes from EZK116) or socket 2 (for fuel injection codes from LH2.4) and repeat the above.
Erasing Fault Codes.
After you have retrieved all the Fault Codes in the steps above, you should erase the system memory.
* Repeat the steps above and read the fault codes again.
* Press and hold the button for more than five seconds, then release it.
* When the LED lights, press the button again for more than five seconds and release. If the LED goes off, then the memory is cleared.
* To test that memory is cleared, press the button again for >1 second and <3>1 and <3>1 and <3>1 and <3>1 and <3 seconds before pressing again).
* The diagnostic unit then tests the EGR system controller which you can hear or feel.
* Exit by switching off the ignition.
LH2.4 Fuel Injection Fault Codes (DTC):
Socket position 2.
(The * means that the CEL is lit)
1-1-1 No faults detected.
1-1-2 Fault in control module.
1-1-3* Short-term fuel trim. Faulty control. Fuel trim (lambda control) too lean or rich.
1-2-1* Mass air flow (
MAF
) sensor signal. Faulty signal to/from Air Mass Meter.
1-2-3* Engine coolant temperature (ECT) sensor. Signal missing to/from coolant temp. sensor.
1-3-1 Engine speed signal from ignition system. Signal missing.
1-3-2 Battery voltage. Battery voltage too low/high.
1-3-3 Throttle position (TP) switch at engine idle. Throttle switch idle setting faulty or grounding fault.
2-1-2* Heated oxygen sensor (HO2S) signal. Faulty or missing signal.
2-1-3 Throttle position (TP) switch at full load. Faulty or missing signal.
2-2-1* Long-term fuel trim, part load. Lean part load.
2-2-3 Idle air control (IAC) valve signal. Faulty or missing signal.
2-3-1* Fuel trim (lambda control) too lean or too rich at part load.
2-3-2* Fuel trim (lambda control) too lean or too rich at idle.
3-1-1 Vehicle speed signal (VSS). Faulty or missing signal. (Also signal from speedometer).
3-1-2 Knock enrichment signal from ignition system. Faulty signal.
3-2-2 Mass air flow sensor (
MAF
). Air Mass Meter wire burn-off signal absent or faulty.
3-4-4 Exhaust gas temperature sensor. Faulty.
EZK 116 Ignition Fault Codes (DTC):
Socket position 6.
(The * means that the CEL is lit)
1-1-1 No faults detected.
1-4-2* Fault in control module.
1-4-3* Knock sensor (KS) signal. Faulty or missing signal.
1-4-4* Load signal. Faulty or missing signal.
1-5-4* EGR. EGR system flow too high.
2-1-4 Engine speed (RPM) sensor. Intermittently absent.
2-2-4 Engine coolant temperature (ECT) sensor. Faulty or missing signal.
2-3-4 Throttle position (TP) switch signal. Faulty or missing signal.
2-4-1* EGR (NTC). EGR system flow too low.
2-4-1* EGR (PTC). EGR system flow too low.
4-1-3* EGR temperature sensor signal (NTC). Faulty or missing signal.
4-1-3* EGR temperature sensor signal (PTC). Faulty or missing signal.
Special Fault Codes (DTC):
ABS
Fault Codes (DTC):
Socket position 3.
1–1–1 No fault detected
1–2–5 Faulty signal from at least one wheel sensor
1–3–5 Fault in control module
1–4–2 Brake light switch, open circuit
1–5–1 L/H front wheel sensor, open or short–circ. to supply
1–5–2 R/H front wheel sensor, open or short–circ. to supply
1–5–5 Rear axle sensor, open or short–circ. to supply
2–1–5 Valve relay, open–circuit or short–circuit
2–3–1 L/H front wheel sensor, signal absent
2–3–2 R/H front wheel sensor, signal absent
2–3–5 Rear axle sensor, signal absent
4–1–1 L/H front wheel valve, open or short–circ.
4–1–3 R/H front wheel valve, open or short–circ.
4–1–5 Rear valve open or short–circ.
4–4–3 Pump motor/relay electrical or mechanical fault
TCU Fault Codes (DTC):
Socket position 5.
2-4-2 Turbo control valve. Open-circuit or shorted.
3-1-2 Knocking information. Signal faulty.
3-4-2 A/C blocking relay. Signal faulty.
4-2-1 Pressure sensor. Faulty boost pressure.
4-2-2 Exhaust gas temperature controller. Signal faulty.
4-2-3 Throttle position sensor. Signal faulty.
4-2-4 Load signal. Signal faulty.
4-3-1 Temperature sensor. Signal missing.
Feilkodeavlesning LH2.4
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