SES light blinking 4.3 vortec

[Michael Lynam]

So my SES light is blinking. Here’s the thing….I have replaced the spark plugs, wires and distributor, and were all gapped right and were torqued right, and not to mention that I have already cleaned my egr valve and still the same issue. The codes showed random misfire and pcm issue (p1638 I think….F terminal). Sooooo I’m pretty much out of options….any help would greatly be appreciated!!!

Topic

[Michael Lynam]

Oh…and the distributor was even timed right too

[Richard Kirshy]

Blinking SES indicator:
The check engine light is most likely to blink if it’s a severe constant problem, like an occurring ignition misfire, injector or a temperature sensor problem, that have an essential part of the engines running. In rare cases, there could also be an internal engine problem or a faulty engine control unit. From experience, a flashing check engine light is most often a misfire, EGR or an exhaust temperature sensor.
Misfires on one or several cylinders (Most common)
Faulty Spark plugs/Coils
Faulty Engine Sensors(Coolant, air temperature, exhaust temperature sensor etc)
Faulty EGR valve
Faulty/Bad Injectors
Faulty Crankshaft/Camshaft sensor
Exhaust emission problems
Boost/Overcharging problems
Internal Engine problem ( low compression due to rings or valve train )
EVAP trouble codes
Faulty Engine control unit (Rare)

P1638 CHEVROLET – Generator ‘F’ Terminal Circuit Conditions
Possible causes
Faulty Generator (Alternator)
Generator harness is open or shorted
Generator circuit poor electrical connection
Powertrain Control Module (PCM) programming
Faulty Powertrain Control Module (PCM)

[Kyle]

Have you checked vacuum leaks, evap (common issues on them), fuel trims, charging system wont ever throw an SES light on those so dont worry about that mine sees 15.6 volts on my 300amp alt daily no issue. I had problems with my distributors cap and rotor randomly but aslong as you bolted it down when the engine was at TDC then your good since timing advance on those is all ecu controlled.

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