2002 Saturn L300 codes P1780, P0502 no power

Tiny
VARMINT54
  • MEMBER
  • 2002 SATURN L300
  • 3.0L
  • V6
  • FWD
  • AUTOMATIC
  • 15,700 MILES
P1780 is a DE torque code and p0502 is only code storied. Used all data pin point test for oss code p0502, oss, checked harness for opens and grounds ok, used a light bulb to load circuits ok. Checked all powers and grounds to tcm and load tested ok. Load tested network from tcm to ecm al check ok. Replaced the oss and then tcm. Codes still present. No power car in limp. There is no pin point test for p1780. Im going to check harness to throttle body to see if I can get the p1780 repaired, on some fords a p1780 is a throttle body.
Monday, December 29th, 2014 AT 7:17 PM

1 Reply

Tiny
HOMER1967
  • MECHANIC
  • 875 POSTS
It has been my experience that on your vehicle, p1780 is a pretty cut and dry issue. It is a faulty crank position sensor causing electrical issues. Replace the crank position sensor and clear the codes and go for a ride, I believe that will also resolve your p0502 issue because now the engine rpm and wheel speed will correlate. With the faultu crank sensor the reported engine rpm does not make up to the reported wheel speed, therefore creating the speed sensor code. That code is not the problem, but a symptom of the problem. Replace the crank sensor and let me know how that does. The sensor is located behind the harmonic balancer in the lower front center of the engine, it has an electrical connector that you have to unplug and one bolt that holds it in. Be sure to install the new o ring with the new sensor to prevent an oil leak and contamination of the new sensor.
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Thursday, January 1st, 2015 AT 9:19 AM

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