System Testing: Notes

1. If trouble codes exist and diagnostic circuit check has been performed, compare code with appropriate code chart for circuits and components associated with trouble code(s). Trouble code flow charts are arranged in alphabetical order by each model. A test No. has been assigned each chart. The test No. and trouble code are in numerical order for each model. All ECU pin identifications are at end of TROUBLE CODES & PROBABLE CAUSE  charts.
2. If no code is present, circuit checking is necessary. Each model has an ECU PIN VOLTAGE TEST table after DIAGNOSTIC CIRCUIT CHECK  flow chart. DIAGNOSTIC CIRCUIT CHECK  flow chart is the first flow chart on each model. Using ECU PIN VOLTAGE TEST table, check appropriate circuits using the test No. in the right column of the appropriate table.
3. Component testing will also be necessary. All component testing available from manufacturer and pertaining to CEC, follow the CEC flow charts. For components not covered, see appropriate article in FUEL or DISTRIBUTORS & IGNITION SYSTEMS.

Code No.	Circuit Affected
No Code	System Normal
11	ECU (B+)
12 & 13	RPM Signal
14	Ignition Signal
21	Oxygen Sensor Signal
22	Coolant Temp. Sensor Signal
23	Intake Air Temp. Sensor Signal
24	Intake Air Temp. Sensor Signal
25 (1)	Lean Air/Fuel Mixture
26 (1)	Rich Air/Fuel Mixture
31	Airflow Meter Signal
32	Airflow Meter Signal (2) HAC Sensor Signal
34 (2)	Turbocharger Pressure
35 (3)	Turbocharger Pressure
41	Throttle Position Sensor Signal
42	Vehicle Speed Sensor Signal
43	Starter Signal
51	Switch Signal
52 (4)	Knock Sensor Signal
53 (4)	Knock Sensor Control (ECU)
54 (3)	Intercooler ECU Signal
71 (5)	EGR System Malfunction
(1) Only applicable to 3S-GE and 4WD models. (2) Only applicable to 4WD models. (3) Only applicable to 4WD models. (4) Only applicable to 4WD models. (5) Only applicable to 3S-GE and Calif. applications oF 4WD models.

Code No.	Probable Cause
11	Main Relay and/or Circuit, Ignition Switch and/or Circuit, ECU
12	Distributor and/or Circuit, Starter Signal, ECU
13	Distributor and/or Circuit, ECU
14	Ignition Coil, Ignitor and/or Circuit, ECU
21	O2 Sensor and/or O2 Heater Signal and/or Circuit, ECU
22	Coolant Temp. Sensor and/or Circuit, ECU
24	Intake Air Temp. Sensor or Circuit, ECU
25 (1)	Injector and/or Ckt, O2 Sensor and/or, Ckt, Fuel Line Pressure, Airflow Meter, Coolant Temp. Sensor, Ignition System, ECU
26 (1)	Injector and/or Ckt, Fuel Line Pressure, Cold Start Injector, Airflow Meter, Coolant Temp. Sensor, ECU
31	Airflow Meter and/or Circuit, ECU
34 (2)	Turbo, Turbo Pressure Sensor and/or Circuit, ECU
35 (2)	Turbo Pressure Sensor and/or Ckt, Airflow Meter, ECU, Intercooler
41	Throttle Position Sensor and/or Circuit, ECU
42	Speed Sensor and/or Circuit, ECU
43	Ignition Switch and/or Circuit, ECU
51	Throttle Position Sensor and/or Ckt A/C Switch Ckt, A/C Amplifier, ECU Neutral/Start Switch and/or Ckt, Accelerator Pedal and/or Cable
52 (3)	Knock Sensor or Circuit, ECU
53 (3)	ECU
54 (4)	Intercooler, Coolant Level Sensor and/or Ckt, Intercooler Water Pump and/or Ckt, Intercooler ECU, ECU
71 (5)	EGR System, EGR Gas Temp. Sensor and/or Ckt BVSV for EGR and/or Ckt, ECU
(1) 4WD & 3S-GE California models only. (2) On 4WD models. (3) On 4WD models. (4) On 4WD models. (5) 4WD California models only.