1995 Lexus SC 400FACTORY OEM SERVICE PROCEDURE

Diagnostic Trouble Code Definitions

DIAGNOSTIC TROUBLE CODE DEFINITIONS (1)

Code Definition
12 No "G", "G1", "G2" or "NE" Ignition Signal To ECM Within 2 Seconds After Engine Is Cranked, Open In "G-" Circuit
13 No "NE" Ignition Signal To ECM When Engine Speed Is Greater Than Approximately 1000 RPM, "NE" Signal Does Not Pulse 12 Times To ECM During Interval Between "G1" and "G2" Pulses
14 No "IGF" Ignition Signal To ECM From Ignitor Several Times In Succession
15 No "IGF" Ignition Signal To ECM From Ignitor Several Times In Succession
16 Fault In Communications Between Engine Central Processing Unit (CPU) and Electronic Controlled Transmission (ECT) CPU In ECM
21 Defective O2 Sensor, Open Or Short Circuit In O2 Sensor Signal
22 Open Or Short Circuit In Engine Coolant Temperature Sensor Signal
24 Open Or Short Circuit In Intake Air Temp. Sensor Signal
25 Lean Signal Sent By O2 Sensor For Several Seconds
26 Rich Signal Sent By O2 Sensor For Several Seconds
27 Open Or Short Circuit In Sub-O2 Sensor Signal
28 Defective O2 Sensor, Open Or Short Circuit In O2 Sensor Signal
29 Open Or Short Circuit In Sub-O2 Sensor Signal
31 Open Or Short Circuit In Airflow Meter Or MAP Sensor Signal
35 Open Or Short Circuit In BARO Sensor
41 Open Or Short Circuit In Throttle Position Sensor Signal
42 No Signal From Vehicle Speed Sensor For Several Seconds
43 No Starter Signal To ECM
47 Open Or Short Circuit In Sub-Throttle Position Sensor Signal
48 Open Or Short Circuit In Vacuum Switching Circuit Of Air Switching Valve
51 (2) Problem In One Of 3 Circuits Monitored By ECM
52 Open Or Short Circuit In Knock Sensor Signal
53 Knock Control In ECM Is Faulty
55 Open Or Short Circuit In Knock Sensor Signal
71 EGR Gas Temperature Less Than Predetermined Level During EGR Control
78 Open Or Short Circuit In Fuel Pump Control Circuit Or Fuel Pump Electronic Control Unit (ECU)
(1) Listed are possible areas causing trouble codes. Not all trouble codes are used on all models.
(2) Throttle position sensor, Park/Neutral switch and A/C Signal circuits are monitored.
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