manicmechanic007
5 Year Member
Same here our Ford manuals had incorrect wire colors for us to chase.At least it is not a GM product. I run into incomplete or just wrong diagnostic routines all the time from the GM service manual. Had a Siverado last week that had a Knock sensor code. Diagnostic routine had me check the voltage at the sensor, (had to remove the starter to access), it said that if I had over 2 volts at pin #2 with the key on to replace the ECM (computer), So I did and then programed the ECM to the vehicle. After all of that, same problem. Turns out, that of the 3 pages of diagnostic routines, at the bottom of the last page it said that if the voltage on pin #2 was between 2 and 4 volts to replace the knock sensor...
WTF is that step not BEFORE, or instead of, the step that says to replace ECM on page 1?
At least it was a warranty repair and GM gets to eat the part and diagnostic time instead of the customer.
I could list several more example of wrong or missing diagnostic steps in the service manual. It gets very frustrating to spend hours chasing wrong information. I asked the shop foreman how all of this stuff gets so messed up and he just shrugs and says, "you are asking the wrong guy, go ask GM". Thanks man, that helps...a lot.