96 Blazer codes (what do they Mean)

[rudis95]

I went to Autozone and got the obd code scaner and got this codes but don't know what they mean or where to start.

The codes are
1)P0122 2)p171 3)p174

4)p0300 5)p0420 6)p1406

Can Anyone please help me.

[TomB985]

Well, I may not be a professional tech like MT-2500 or any of the other really knowledgable guys here, but here goes.....

P0122 = Throttle Position Sensor circuit low input
P0171 = System Adaptive Fuel too lean
P0174 = System too lean
P0300 = Random cylinder misfire
P0420 = Catylist system efficiency below threshold
P1406 = EGR position sensor performance

My best guess would be to start with the TPS and work backward. Everything else here is affected by the throttle position sensor, so I'd replace that, check the MAP sensor, and give it a shot.

[MT-2500]

Originally Posted by TomB985

Well, I may not be a professional tech like MT-2500 or any of the other really knowledgable guys here, but here goes.....

P0122 = Throttle Position Sensor circuit low input
P0171 = System Adaptive Fuel too lean
P0174 = System too lean
P0300 = Random cylinder misfire
P0420 = Catylist system efficiency below threshold
P1406 = EGR position sensor performance

My best guess would be to start with the TPS and work backward. Everything else here is affected by the throttle position sensor, so I'd replace that, check the MAP sensor, and give it a shot.

Good advise there Tom.
Some repair manuals say to start with the lowest no code.
But remember a code does not say replace the sensor it says to check it out.

With that many codes i would sugget that the codes be cleared and see which one comes back first.
MT

[MT-2500]

Originally Posted by rudis95

I went to Autozone and got the obd code scaner and got this codes but don't know what they mean or where to start.

The codes are
1)P0122 2)p171 3)p174

4)p0300 5)p0420 6)p1406

Can Anyone please help me.

As Tom said check the TPS sensor.
First check the voltage on it.

Also we need more info.
What mileage and engine?
How is the tune up end like mileage on plugs and filters and what kind of plugs?
How is the fuel pressure?

[TomB985]

Originally Posted by MT-2500

But remember a code does not say replace the sensor it says to check it out.

Good point...how would you test that sensor? I've tested the resistence on a few sensors in the past, and even though they were within tolerance, they were causing the problem...Short of forking out a few hundred on a data logging scan tool, what's the best way to check these things?

[MT-2500]

On sensor testing you need a good engine capable scanner to see what the sensor is feeding the pcm and what pcm is reading.

But a lot of sensors the only true test is a lab scope to watch for drop outs and read square wave.

A few sensors you can take a voltage or ohm reading with a good volt/ohm meter.
But many like MAF sensors and a baro sensors you can not check with a volt metor.

The tps sensor should have 4.5 -5 volts key on votage to it.
And a good ground.
Voltage feed to pcm should be .5 to 1 volt closed throttle and swing to 4.5 -5 volts wide open throttle with no drop outs.