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Jim
Grant has been working in the automotive industry for over twenty
years. In addition, Jim is an ASE Master Technician with advanced
L/1 certification. He works as manager and technician in his
family's automotive business in New Hampshire. He writes weekly
automotive consumer columns and is editor of an automotive newsletter
that is circulated throughout North America. |
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Jim Grant's Tech Tips
'97
Pontiac Grand AM, A-lot of Parts and Computer Code
Q:
My ’97 Pontiac
Grand AM has a computer code #1336 that has been down loaded in the last
6 months. I have changed the oxygen sensor, crankshaft position sensor,
PCM, plugs, ignition cap assembly, catalytic converter, air filter, thermostat,
temperature sensor for the coolant and the engine light is still on. So
do you have any recommendations?
- Fred Z.
A:
Your vehicle’s
computer is only telling you that it wants to learn something. Diagnostic
Trouble Code (DTC) # P1336 simply means that the computer has not learned
and recorded the variations in crankshaft of the engine. The crankshaft
in your vehicle’s engine has a wheel with notches that corresponds
with piston position. The crankshaft position sensor reports to the computer
each time one of the notches passes by the sensor. After all the computer
needs to know where the piston is so it can add fuel or create spark at
the spark plug at the right time. But the computer needs to take this
knowledge of crankshaft position to the next level. It needs to know and
record any variations. Engines and computer sensors are mass-produced
and, in theory, all of these parts should be identical. But it is not
the case and the engineers allowed for this in the software of the computer.
Once in your vehicle’s lifetime the computer needs to learn crankshaft
variations and this is performed at the factory. This lifetime information
is fine unless the crankshaft position sensor is disturbed (unbolted),
replaced or if the vehicle computer is replaced. You’ve done both!
The check engine light will not turn off until the computer is commanded
to perform a Crankshaft Position Sensor Variation Learning Procedure.
To perform this step requires a computer scan tool to access the learn
command mode of the software. A little class time should be all that is
needed to turn your check engine light off.
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