Hi Black Jester,
Engine and transmission codes are different. When the D4 light is blinking, the trans ECM has detected a fault and a code 4 means trhe speed sensor or its ciruit is faulty. If it does shouw with the Check engine light blinking when retrieving codes, it should show as 17 blinks. You have mistaken the trans trouble code for the engine trouble codes.
You would need to replace the Vehicle Speed Sensor to get the speedometer working correctly again and get rid of the blinking D4 light.
When the speedometer is not working correctly, fuel consumption and shifting points would be affected.
Wednesday, September 30th, 2009 AT 12:43 PM