QuestionMy 93 Transport (3.8 162000 miles) has a rough idle when you come to a stop. It starts and runs fine except when you are stopped and in Drive or Park. I scanned it and it's coming up with a code 43 (spark control circuitry problem). It's a vague description and I don't know how to test it to see if it needs replacement.
Any info would be appreciated.
Thanks in Advance,
Patrick
AnswerHi,Patrick
Code 43 is a knock sensor fault code,part of the ignition control code,ill give you the diagnostic tree as follows:
Locate the knock sensor,it is on the right side of the engine block,the engine sits sideways its on the back half of the engine block,you need to gain access under the vehicle.
It is recommended to use a scan tool to monitor knock sensor data,it should remain at 0 deg during engine idle and normal temp if knock sensor values show retard 4-20 deg then the ckts and the sensor need to be tested,ill give you the ckt tests.
Disconnect knock sensor connector,key on measure voltage from sensor wire to ground,its a drk blue wire,voltage should be at 4-6 volts,if it is over 6 volts,either the ckt is shorted to voltage or a failed PCM,if under 4 volts,ckt is shorted to ground,check the wire for rubbed through or pinched,if wire tested good then its a failed PCM.
If the voltage shows 4-6 volts,test the knock sensor,ohm check the terminal in the sensor to good ground,reading should be at 3.3 ohm to 4.5ohm,if it is not within that range then its a failed knock sensor,if the reading are ok then check the terminal connector or the wire for short or its a failed PCM and PROM.let me know what you find.
ED
