Entered by Carey Morris from the 1994 Engine Repair Manual
The ECM contains a built-in self-diagnosis system by which troubles with the engine signal network are detected and a malfunction indicator lamp on the instrument panel lights up.
By analyzing various signals as shown in a later table (see table below) the Engine Control Module (ECM) detects system malfunctions relating to the sensors or actuators.
In the normal mode, the self-diagnosis system monitors 19 items, indicated by code No. as shown (see table below). A malfunction indicator lamp informs the driver that a malfunction has been detected. The lamp goes off automatically when the malfunction has been repaired. But the diagnostic trouble code(s) remains stored in the ECM memory (except for code Nos. 16 and 53). The ECM stores the code(s) until it is cleared by removing the EFI No. 1 fuse with the ignition switch off.
The diagnostic trouble code can be read by the number of blinks of the malfunction indicator lamp when TE1 and E1 terminals on the data link connector 1 or 2 are connected. When 2 or more codes are indicated, the lowest number (code) will appear first.
In the test mode, 13 items, indicated by code No. as shown (see table below) are monitored. If a malfunction is detected in any one of the systems indicated by code Nos. 13, 21, 22, 24, 25, 26, 27, 35, 41, 47, 71 and 78 the ECM lights the malfunction indicator lamp to warn the technician that malfunction has been detected. In this case, TE2 and E1 terminals on the data link connector 2 should be connected as shown later.
In the test mode, even if the malfunction is corrected, the malfunction code is stored in the ECM memory even when the ignition switch is off (except code Nos. 42 and 51). This also applies in the normal mode. The diagnostic trouble mode (normal or test) and the output of the malfunction indicator lamp can be selected by connecting the TE1, TE2 and E1 terminals on the data link connector 2, as shown later.
A test mode function has been added to the functions of the self-diagnosis system of the normal mode for the purpose of detecting malfunctions such as poor contact, which are difficult to detect in the normal mode. This function fills up the self-diagnosis system. The test mode ca be implemented by the technician following the appropriate procedures of check terminal connection and operation described later.
Diagnosis Inspection (Normal Mode)
DIAGNOSTIC TROUBLE CODE CHECK
DIAGNOSTIC TROUBLE CODE CHART (2JZ-GTE)
|Circuit||Diag.. Trouble Code Detecting Condition||
|Normal Mode||Test Mode||Memory|
|-||Normal||No code is recorded||-||-||-||-|
|12||G, NE Signal (No. 1)||No "NE" or "G1" and "G2 signal to ECM for 2 sec. or more after cranking.||
G, NE Signal (No. 2)
|No NE signal to ECM for 0.1 sec. or more at 1,000 rpm or more.||
|NE signal does not pulse 12 times to ECM during the interval between G1 and G2 pulses.||
|Deviation in G (G1, G2) and NE signal continues for 3 sec. during idling (throttle fully closed) after engine warmed up.||
|No IGF signal to ECM for 4~7 consecutive IGT signals with engine speed less than 3,000 rpm.||
A/T Control Signal
|Fault in communications between the engine CPU and A/T CPU in the ECM.||
Main Heated Oxygen Sensor Signal
|Open or short in heater circuit of main heated oxygen sensor (Fr) for 0.5 sec. or more.||
|Main heated oxygen sensor
signal voltage is reduced to between 0.35V and 0.70V for 60 sec. under condition
a) ~ (d). (2 trip detection logic)
a). Engine coolant temp.: Between 80° C (176°F) and 95°C (203°F)
|22||Engine Coolant Temp. Sensor Circuit||Open or short in engine coolant temp. sensor circuit for 0.5 sec or more.||
|24||Intake Air Temp. Sensor Signal||Open or short in intake air temp. sensor circuit for 0.5 sec. or more.||
|25||Air-Fuel Ratio Lean Malfunction|
|26||Air-Fuel Ratio Rich Malfunction|
|27||Sub Heated Oxygen Sensor Signal|
|31||Mass Air Flow Meter Circuit|
|34||Turbo Pressure Malfunction|
|35||Turbo Pressure Sensor Circuit|
|35(?)||Barometric Pressure Sensor Circuit|
|42||No. 1 Vehicle Speed Sensor Signal (for A/T)|
|No. 1 Vehicle Speed Sensor Signal (for M/T)|
|47||Sub-Throttle Position Sensor Signal|
|52||Knock Sensor Signal (front side)|
|53||Knock Control Signal||Engine control computer (for knock control) malfunction at engine speed between 650 rpm and 5,200 rpm.||
|55||Knock Sensor Signal (rear side)|
|71||EGR System Malfunction|
|78||Fuel Pump Control Signal|
|51||Switch Condition Signal||