1992 Toyota Paseo Diagnostics

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Written by Shawn at tercelclub.com

Friday, 08 December 2006

The Check Engine Light (CEL) is never a fun thing to see come on in your dash, but it also might be something easy to fix. You can check your own CEL codes with only a small piece of wire or paper clip (on OBD cars; for OBD II scroll down to the bottom for what the codes mean), and know right away what your problem is. This guide was pieced together from a few articles, and should give you a good starting place to find out what is wrong with your Tercel or Paseo.

The following information was found at about.com, obd-codes.com, and off-road.com. All credit goes to these sites for authoring this article.

The first thing you should do is check the computer for any stored codes. Here's how to do it on your OBD Car (1994-95 or older).

EXTRACTING DIAGNOSTIC CODES (OBD):

Confirm initial conditions:
1. Battery voltage is at least 11 volts.
2. Throttle valve is fully closed.
3. Transmission is in neutral.
4. All accessories turned OFF.
Connect a service wire across terminals T and E1 of the engine check connector. You can use a small wire or paper clip for this as well.
Turn ignition switch ON, but DO NOT start engine.

Read the diagnostic code(s) as indicated by the number of flashes of the "CHECK ENGINE" light on the instrument cluster.
After codes are extracted, turn-off ignition switch and remove service wire.

DIAGNOSIS INDICATION - If no malfunction codes are stored in the ECU, the "CHECK ENGINE" light will flash ON and OFF two times per second repeatedly. In the event of a stored code, the light will flash every 0.5 second to indicate the first digit of the diagnostic code. This will be followed by a 1.5 second pause and 0.5 second flashes to indicate the second digit of the code.

If there are two or more codes stored in memory, there will be a 2.5 second pause between each code. After all the codes have been displayed, there will be a 4.5 second pause before the codes will be repeated in the same order. This sequence will continue as long as the check connector terminals remain shorted.

In the event that multiple codes are stored, the codes will display in numerical ascending order, with the lowest numbered code displayed first. All codes are retained in the ECU memory, until they are canceled using the proper procedure.

Once we know what the codes are, we can go from there.

(Click here to view just the table)

One-Digit Code	Two-Digit Code	Possible cause of Code/Symptom
1	None	SYSTEM NORMAL
--	11	LOSS OF POWER SUPPLY TO ECU --IGNITION SWITCH/CIRCUIT --MAIN RELAY/CIRCUIT --ECU
6	12	RPM SIGNAL-NO SIGNAL TO ECU FROM DISTRIBUTOR ("Ne" OR "G") AFTER ENGINE HAS BEEN CRANKED --DISTRIBUTOR/CIRCUIT --STARTERSIGNAL CIRCUIT --IGNITER/IGNITER CIRCUIT --ECU
--	13	SAME AS ABOVE BUT AFTER ENGINE HAS RUN AT 1,000-1,500 RPM --DISTRIBUTOR/DISTRIBUTOR CIRCUIT --ECU
3	14	IGNITION SIGNAL--NO "IGF" SIGNAL TO ECU --IGNITER/IGNITER CIRCUIT --IGNITER AND IGNITION COIL/CIRCUIT --ECU
5	21	OXYGEN SENSOR SIGNAL/OXYGEN SENSOR HEATER SIGNAL OPEN OR SHORT IN OXYGEN SENSOR OR OXYGEN SENSOR SIGNAL
4	22	WATER TEMPERATURE SENSOR SIGNAL --OPEN OR SHORT IN WATER TEMP. SENSOR SIGNAL --WATER TEMPERATURE SENSOR CIRCUIT --WATER TEMPERATURE SENSOR --ECU
8	24	INTAKE AIR TEMPERATURE SENSOR SIGNAL --OPEN OR SHORT IN INTAKE AIR TEMP. SIGNAL --INTAKE AIR TEMPERATURE CIRCUIT --INTAKE AIR TEMPERATURE SENSOR --ECU
--	25	AIR/FUEL RATIO LEAN INDICATOR --LEAN SIGNAL SENT TO ECU FROM O2 SENSOR --INJECTOR FAULT(S) --FUEL PRESSURE --OXYGEN SENSOR --AIRFLOW METER OR MAP SENSOR --IGNITION --ECU
--	26	AIR/FUEL RATIO RICH INDICATOR --SAME AS ABOVE --COLD START INJECTOR
--	27	SUB-OXYGEN SENSOR CIRCUIT OR SUB-OXYGEN SENSOR HEATER CIRCUIT --SUB OXYGEN SENSOR/HEATER/CIRCUIT --ECU
--	28	No.2 OXYGEN SENSOR/OXYGEN SENSOR HEATER --SAME AS CODE 21
2	31	MANIFOLD AND/OR AIRFLOW METER SENSOR SIGNAL CIRCUIT --AIRFLOW METER/CIRCUIT --MANIFOLD PRESSURE SENSOR/CIRCUIT --ECU
--	32	AIRFLOW METER SIGNAL (VANE-TYPE) --AIRFLOW METER./CIRCUIT --ECU
14	34	TURBOCHARGER PRESSURE --ABNORMAL TURBOCHARGER PRESSURE --TURBO CHARGER --AIRFLOW METER/MANIFOLD/TURBOCHARGER PRESSURE SENSOR --INTERCOOLER SYSTEM --ECU
--	35	TURBOCHARGER PRESSURE SENSOR SIGNAL --TURBOCHARGER PRESSURE SENSOR --ECU
7	41	THROTTLE POSITION SENSOR SIGNAL --OPEN OR SHORT IN TPS SIGNAL --TPS SENSOR --TPS SIGNAL/CIRCUIT --ECU
9	42	VEHICLE SPEED SENSOR SIGNAL CIRCUIT --NO SPD. SIGNAL FOR SEVERAL SECONDS WHILE VEHICLE IS OPERATED UNDER HEAVY LOAD (TPS/MAP/AIR FLOW INPUTS) --SPEED SENSOR/CIRCUIT --ECU
10	43	STARTER SIGNAL --NO "STA" SIGNAL TO ECU UNTIL ENGINE SPEED EXCEEDS 800RPM --IGNITION SWITCH/CIRCUIT --ECU
11	51	SWITCH SIGNALS IDL (tps) CONTACTS OFF, NEUTRAL START SWITCH OFF, A/C SWITCH "ON" SIGNAL TO ECU WITH DIAGNOSTIC CHECK CONNECTOR SHORTED --A/C SWITCH/CIRCUIT --A/C AMPLIFIER --TPS/CIRCUIT --NEUTRAL START SWITCH/CIRCUIT --ECU
12	52	KNOCK SENSOR SIGNAL --OPEN OR SHORT IN KNOCK SENSOR SIGNAL --KNOCK SENSOR/CIRCUIT --ECU
13	53	KNOCK CONTROL SIGNAL IN ECU --ECU
--	71	EGR VALVE MALFUNCTION --EXHAUST GAS TEMPEATURE BELOW SPEC. FOR EGR CONTROL --EGR SYSTEM --EGR GAS TEMPERATURE SENSOR/CIRCUIT
--	72	AIR CONDITIONER COMPRESSOR RELAY/RELAY SIGNAL --A/C COMPRESSOR RELAY/CIRCUIT --ECU

While a lot of the possible faults in the EFI system point to the ECU iteself, it should be noted that ECU failure is not common. The ECU should be replaced only as a last resort or if all diagnosises points to a bad ECU. Usually, troublesome EFI problems are a result of poor grounds, shorted wiring, and bad connectons at sensors.When all else fails, carefully consult your factory repair manual. It contains more comprehensive diagnostic information and great electrical wiring diagrams.

For OBD II: Autozone and other car parts stores will check your diagnostic codes for free during normal business hours. If you own a scanner, the following are Toyota Specific Codes

(Click here to view just the table)

Code	Description
P1100	BARO Sensor Circuit.
P1120	Accelerator Pedal Position Sensor Circuit.
P1121	Accelerator Pedal Position Sensor Range/Performance Problem.
P1125	Throttle Control Motor Circuit.
P1126	Magnetic Clutch Circuit.
P1127	ETCS Actuator Power Source Circuit.
P1128	Throttle Control Motor Lock.
P1129	Electric Throttle Control System.
P1130	Air/Fuel Sensor Circuit Range/Performance. (Bank 1 Sensor 1)
P1133	Air/Fuel Sensor Circuit Response. (Bank 1 Sensor 1)
P1135	Air/Fuel Sensor Heater Circuit Response. (Bank 1 Sensor 1)
P1150	Air/Fuel Sensor Circuit Range/Performance. (Bank 1 Sensor 2)
P1153	Air/Fuel Sensor Circuit Response. (Bank 1 Sensor 2)
P1155	Air/Fuel Sensor Heater Circuit. (Bank 1 Sensor 2)
P1200	Fuel Pump Relay Circuit.
P1300	Igniter Circuit Malfunction - No. 1.
P1310	Igniter Circuit Malfunction - No. 2.
P1335	No Crankshaft Position Sensor Signal - Engine Running.
P1349	VVT System.
P1400	Sub-Throttle Position Sensor.
P1401	Sub-Throttle Position Sensor Range/Performance Problem.
P1405	Turbo Pressure Sensor Circuit.
P1406	Turbo Pressure Sensor Range/Performance Problem.
P1410	EGR Valve Position Sensor Circuit Malfunction.
P1411	EGR Valve Position Sensor Circuit Range/Performance.
P1500	Starter Signal Circuit.
P1510	Boost Pressure Control Circuit.
P1511	Boost Pressure Low.
P1512	Boost Pressure High.
P1520	Stop Lamp Switch Signal Malfunction.
P1565	Cruise Control Main Switch Circuit.
P1600	ECM BATT Malfunction
P1605	Knock Control CPU.
P1630	Traction Control System.
P1633	ECM.
P1652	Idle Air Control Valve Control Circuit.
P1656	OCV Circuit.
P1658	Wastegate Valve Control Circuit.
P1661	EGR Circuit.
P1662	EGR by-pass Valve Control Circuit.
P1780	Park/Neutral Position Switch Malfunction (Only For A/T)

Last Updated Tuesday, 27 November 2007

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