02 gmc 4.8 code po336 i replaced the sensor but still won;t start

You actually have 4 of them, an upstream and a downstream on each bank of cylinders. You only replace the one that failed. The code will tell you, Bank 1 or Bank 2, and Sensor 1 or Sensor 2.

https://www.google.com/search?q=2016+gmc+sierra+1500+replace+o2+sensor

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Who replaced the crank sensor ? Did they do a crankshaft position relearn ? P0336 Chevrolet Crankshaft Position Sensor Circuit Range Performance

year/make/model??? P0336 is a crank sensor circuit code. P0340 is a cam sensor circuit code

P0038 - HO2S Heater Control Circuit High Bank 1 Sensor 2
P0128 - Coolant Thermostat (Coolant Temp Below Thermostat Regulating Temperature)
P0336 - Crankshaft Position Sensor Circuit A Range/Performance
P0386 - CKP Sensor B Circuit Performance.
your most likely need to replace the crankshaft sensor and probably will take care of the 0336 and 0338 codes.
you then need to check your coolant level, if low fill and look for leaks, if not low, most likely replacing the thermostat will correct other two codes

Code "P0336" is the code for a crankshaft position sensor (CPS) fault. The connection may just be loose but it probably needs to be replaced.

Recheck your connections. May be a stretched timing chain. Incorrect correlation between a CKP and CMP will cause these codes. Doesn't mean the sensors are bad, it may be the chain.

Closed loop the ECM is using the feedback from the 02 sensor, open loop the ECM ignores the 02 sensor, this is a emission strategy on the vehicle, has nothing to do with the car not starting.

I punched in code po336 for a bing search,
and it says that it could be
PO336
Crankshaft Position Sensor Signal Range / Performance
But it may be for another car.

What was your engine size and submodel? My reference on the Internet didn't have fault codes for your vehicle.

CODE PO325 - KNOCK SENSOR. CODE PO335 -CRANK SHAFT POSITION SENSOR. CODE PO336 - I DID NOT SEE CODE PO336.

Cam Sensor