A/c in my 1992 es300 blows hot air and system self check reports problem code 21. what is code 21? had it serviced and everything seems too be working find but still hot. pressure on high side is normal, but pressure on low side is very high. the tech said its the compressor. said its kicking back pressure to low side .thats had for me to believe.

Lexus Instrument cluster repair services. Testing ... - YouTube

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www.youtube.com/watch?v=TSm8hLzA_dM
Apr 14, 2013 - Uploaded by SpeedometerRepair
Instrument cluster testing, On this video we are running the odometer/speedometer, ... Testing speedometer and odometer on a Lexus ES300.

Clearing the codes is simple that is done by removing the fuse of the EFI from junction box 2 for 10 seconds. Make sure to remove the jumper wire and switch the key off before clearing the codes.

Here are some common Lexus vehicles 1990-1995 codes:

Code 12 and Code 13 Rpm signal circuit fault
Code 14 Igniter signal circuit fault
Code 16 ECT control signal fault
Code 21 and Code 28 Main oxygen sensor fault (for ES300; SC300 & GS300 models)
Code 22 Coolant temperature circuit fault
Code 24 Intake temperature sensor circuit fault
Code 25 and Code 26 Air fuel ratio fault (for ES300 & SC300 models)
Code 27 Sub-oxygen sensor circuit fault (for ES300 CA & GS300 models)
Code 31 Low airflow meter voltage (for ES300 and GS300 models)
Code 32 High airflow meter voltage (for ES300 model)
Code 35 Barometric pressure sensor circuit fault (for GS300 & SC300 models)
Code 41 and Code 47 Throttle position sensor circuit fault
Code 42 Vehicle speed sensor circuit fault
Code 43 Starter signal
Code 51 Switch condition signal fault (for ES300; GS300 & SC300 models)
Code 52 Code 52 and Code 55 Knock sensor circuit fault
Code 71 EGR system circuit fault (for ES300; GS300 & SC300 models)
Code 78 Fuel pump control circuit fault (for GS300 & SC300 models)

Under hood, driver side, front side of strut tower, mounted to fenderwell

Note, this is an OBD1 connector. You will need an OBD1 scanner to read codes.

Alternate methods to extract trouble codes:

USING THE ANALOG VOLTMETER See Figures 3 and 4
Service codes will be represented by pulsing or sweeping movements of the voltmeter's needle across the dial face of the voltmeter. Therefore, a single digit number of 3 will be reported by 3 needle sweeps. However, a service code is represented by a 2-digit or 3-digit number, such as 23. As a result, the Self-Test service code of 23 will appear on the voltmeter as 2 needle sweeps, then after a 2 second pause, the needle will sweep 3 times.
Connect the analog voltmeter as follows:

1. Turn the ignition OFF .

Fig. Fig. 3: Voltmeter hook-up

Fig. Fig. 4: Analog voltmeter output code format

1. Set the voltmeter on a DC voltage range to read from 0-20 volts.
2. On all EEC-IV vehicles, connect the voltmeter from the battery positive post to the Self-Test Output (STO) pin of the large Self-Test connector. On all other vehicles, connect the positive voltmeter lead to the EEC STO line and the negative lead to engine ground, then jumper the EEC Self-Test Input (STI) to ground.

USING THE MALFUNCTION INDICATOR LIGHT (MIL) During the Self-Test,a service code is reported by the malfunction indicator light. It will represent itself as a flash on the CHECK ENGINE or SERVICE ENGINE SOON light on the dash panel. A single digit number of 3 will be reported by 3 flashes. However, a service code is represented by a 2-digit or 3-digit number, such as 23. As a result, the Self-Test service code of 23 will appear on the MIL light as 2 flashes, then, after a 2 second pause, the light will flash 3 times.

bad head gasket

you need a FAN temp control switch or relay or run a toGGl switch

Is the inlet and outlet heater hoses hot and if so you have a seperate acuator for your hot/cold door.Check for vacuum there if you have vacuum to the acuator then it must be a faulty acuator or jambed door.

it seems as if there is a clog in the radiator, flush out coolant system and see if this helps.usually when top hose is hot and bottom hose is cold there is a clog somewhere in system. check radiator and make sure coolant is circulating. hope this helps carl,

Sounds like multiple problem's. The a/c sound's like low on freon.The air bag and ses light are seperate systems from the a/c.Any time the service engine light is on it has to do with the engine system,the air bag is also seperate.Need to take in and have the code's checked for the service light and they can also check the air bag system and see what codes are stored and go from there.

probably it just needs freon or a new a c compressor

How often has the coolant been changed? My only guess is that it hasn't and the hoses and the heater core are plugged up with goo and a flush is needed