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The technique of reading fault codes from RAM (random access memory) controller similar to the controller method "GM" and valid in relation to all vehicles equipped with an engine management system "January 4". This article discusses methods of diagnosis on the example of the car VAZ-21093-20.

On the instrument panel of vehicles fuel injection system, installed indicator lamp malfunction "CHECK ENGINE" . It lights up when the ignition is 0.6 sec. and indicates its serviceability and diagnostic health system. In the presence of transient errors in the injection system warning light "CHECK ENGINE" lights up for at least 10 seconds.

If a failure is detected, the controller stores its code in RAM and lights the lamp "CHECK ENGINE" which points to the need for diagnostics and Troubleshooting. In memory of the electronic unit management memorized two-digit error code ( 12-99 ), which indicated that lamp when initializing the output mode codes self-test. Erasing error codes in the RAM of the controller occurs when the power is turned off. If You need to delete it, it is necessary with the ignition off, disconnect the positive terminal of the battery for 10-15 seconds. Accordingly, a self-test should be conducted no less than 10-20 minutes of operation of the vehicle (preferably on different loads), after the last disconnect the battery. --- WARNING --- When you disconnect the battery may be lost preset critical auxiliary devices (radio, alarm, etc.). In this case, you can simply remove fuse to the electric component box, if this circuit is not connected critical devices. Otherwise, you can remove the connector from the electronic unit. In addition, in RAM will be lost correction codes and to restore them (up to 30 minutes of operation) should refrain from dynamic driving and abrupt acceleration.

Diagnostic connector

A Grounding B Initialization mode read codes F T. C. C. (may not be) G control of the pump H, the Speed of data exchange with M Serial code

To initialize the mode of issuance diagnosis codes must be switched off the ignition to close contact "And " and "In " diagnostic connector or contact "In" to the vehicle body and turn on the ignition without starting the engine. The error code displayed flashes the lamp "CHECK ENGINE" in a sequential manner - the MSB of the first, then (after a pause) younger. For example: flash , pause , flash , flash will match code "12"is the performance of self-diagnosis. Upon initialization of this mode, the indicator first three times in a row will give the code "12" and then three times each fault code. If the test code is not displayed " 12 ", means a malfunction in the electric component box control. If the memory controller fault codes are missing, lamp "CHECK ENGINE" will continue to output code " 12 ". In addition, in the scan mode codes can be included relay adventista the engine cooling system and relay clutch of the air conditioner (if installed), and the idling speed controller is set to the cessation of additional air.

Controller diagnostics codes indicated the lamp "CHECK ENGINE"

* 13 - Low signal lambda probe

14 is a Low level signal of the coolant temperature sensor

15 is a High level signal of the coolant temperature sensor

16 - High voltage onboard network

17 - Low voltage onboard network

19 - Error signal of the crankshaft position sensor

21 - High level sensor signal throttle position

22 - Low level sensor signal throttle position

* 23 - High level of the signal of the intake air temperature sensor

24 - No sensor signal vehicle speed

* 25 - Low level signal of the intake air temperature sensor

* 26 - the High level signal of the intake air temperature sensor

27 is a High level signal FROM potentiometer

28 is a Low level signal FROM potentiometer

33 - Error sensor signal air flow (high frequency)

34 - Error sensor signal air flow (low frequency)

35 - Error signal of the engine speed at idle

* 38 - Error signal of a lambda probe

* 41 - Error signal of the phase sensor

43 - Error signal of the sensor detonation

* 44 - Error signal of a lambda probe in the lean burn

* 45 - Error signal of a lambda probe in the enrichment of the fuel mixture

51 - Error read only memory

52 - Error random access memory

* 53 - Error of CSU

* 54 - Error octane-corrector

* 55 - Error electronic control unit

* 61 - Error immobilizer

Codes marked with "*" may not be used, and their corresponding sensors may not be installed.

It should be noted that read the error codes are not always clearly indicate the failure of a sensor or element of the injection system. When the diagnosis to map the data controller, the positive response of the sensors and the specific behavior of the engine at idle and under load. Because the control system of fuel injection is constantly being improved, the table may be missing some fault codes.

After reading the error codes, you must switch off the ignition and after 10-15 sec. remove the jumper on the diagnostic connector.

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