Sephia GS Sedan L4-1.8L (1997)
Air Flow Meter/Sensor: Technical Service Bulletins
Engine Controls - DTC P0170 Ground Improvement
SOURCE: Kia Technician Times
TITLE: DTC P0170 Ground Improvement
APPLIES TO: 95-97 Sephia
SERVICE TIP:
CONDITION
Some 1995 - 1997 vehicles have experienced repeat occurrences of "Check Engine" light illumination where a DTC P0170 - Fuel Trim Malfunction
was retrieved.
CAUSE
This condition is caused by high resistance in the MAF sensor ground circuit which results in excessive negative fuel trims.
CORRECTIVE ACTION
NOTICE
-
A high negative fuel trim is typical of a poor ground connection.
-
Before starting ground improvements, remove any previous ground additions from the EGI wiring harness.
1. After retrieving a P0170 code, make note of the freeze frame data.
a) Record the short fuel trim (SFT) and long term fuel trim (LFT) percentages.
2. Start the engine and allow it to fully warm-up and switch to closed-loop operation as indicated on the scan tool.
3. Using a digital voltmeter, measure the voltage drop from G103 to the MAF sensor connector C135 Pin No. 5.
a) Connect the positive lead to connector C135 Pin No. 5 and the negative lead to G103.
b) If the reading is above 0.060 volts, the EGI harness grounds will need to be improved.
c) If the reading is less than 0.060 volts, then the DTC P0170 has been caused by some other malfunction.
