Engine Controls - Repeat MIL ON/DTC P0170

SOURCE: Kia Technician Times

TITLE: DTC P0170

APPLIES TO: 95-97 Sephia 1.6L

SERVICE TIP:

Some 1995-1997 Sephia's equipped with the 1.6 DOHC engine have experienced repeat occurrences of "Check Engine" light illumination where a DTC P0170 - Fuel Trim Malfunction was retrieved. This condition is caused by high resistance in the MAF sensor ground circuit which results in excessive negative fuel trims.

NOTICE
1.6 DOHC Sephias have a different wiring for ground than the 1.8 DOHC.






1. Connect the voltmeter positive lead to C135-5 of the MAF and connect the negative lead to G103.
2. If the reading is above 0.060 volts, the fuel trim reading will be off enough to set a code.
3. Remove the 6mm bolt at G103.
4. Using a high wattage soldering gun, solder the wires to the lug, then reinstall the bolt.






5. Locate splice S299 in the harness.
NOTICE
- The splice is located in the section of the EGI harness that runs horizontally just above the heater hoses on the bulkhead.
- There are two splices located near each other, S299 has a five BLK/YEL wires is the ground junction for the MAF. S105 has four BLK/YEL wires and supplies 12V to the vehicle speed sensor. DO NOT not mix them up.

6. Carefully remove the electrical tape from the split wrap and expose the wires.
7. Remove the electric tape from S299, and solder the junction with a high wattage soldering gun.
8. Retape the junction, insert the wires into the split wrap, and retape the harness.
9. Start the engine and verify the fuel trim is returning to normal (±7% total long and short term). It will take several minutes for this to occur after the engine goes into closed loop operation.