TROUBLE DIAGNOSIS - SPECIFICATION VALUE

VR38

Description
Component Function Check
Diagnosis Procedure

Description

The specification (SP) value indicates the tolerance of the value that is displayed in “SPEC” in “DATA MONITOR” mode of CONSULT-III during normal operation of the Engine Control System. When the value in “SPEC” in “DATA MONITOR” mode is within the SP value, the Engine Control System is confirmed OK. When the value in “SPEC” in “DATA MONITOR” mode is NOT within the SP value, the Engine Control System may have one or more malfunctions.
The SP value is used to detect malfunctions that may affect the Engine Control System, but will not light the MIL.
The SP value will be displayed for the following three items:

B/FUEL SCHDL (The fuel injection pulse width programmed into ECM prior to any learned on board correction)
A/F ALPHA-B1/B2 (The mean value of air-fuel ratio feedback correction factor per cycle)
MAS A/F SE-B1/B2 (The signal voltage of the mass air flow sensor)

Component Function Check

1.PRECONDITIONING

2.PERFORM SPEC IN DATA MONITOR MODE

Diagnosis Procedure

OVERALL SEQUENCE

DETAILED PROCEDURE

1.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”

2.CHECK “B/FUEL SCHDL”

3.CHECK “B/FUEL SCHDL”

4.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”

5.CHANGE ENGINE OIL

6.CHECK FUEL PRESSURE

7.DETECT MALFUNCTIONING PART

8.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”

9.PERFORM POWER BALANCE TEST

10.DETECT MALFUNCTIONING PART

11.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”

12.CHECK A/F SENSOR 1 FUNCTION

13.CHECK A/F SENSOR 1 CIRCUIT

14.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”

15.DISCONNECT AND RECONNECT ECM HARNESS CONNECTOR

16.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”

17.CHECK “B/FUEL SCHDL”

18.DETECT MALFUNCTIONING PART

19.CHECK INTAKE SYSTEM

20.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”, AND “B/FUEL SCHDL”

21.DISCONNECT AND RECONNECT MASS AIR FLOW SENSOR HARNESS CONNECTOR

22.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”

23.CHECK “MAS A/F SE-B1”, “MAS A/F SE-B2”

24.REPLACE ECM

25.CHECK INTAKE SYSTEM

26.CHECK “B/FUEL SCHDL”

27.CHECK “MAS A/F SE-B1”, “MAS A/F SE-B2”

28.CHECK INTAKE SYSTEM

29.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”, AND “B/FUEL SCHDL”

30.CHECK “B/FUEL SCHDL”