1996 Kia Sephia code P0170

Hi mars919,

Here are the description and diagnostics for the fault code.

DTC P0170: FUEL TRIM MALFUNCTION
Fuel trim malfunction code may be set by:

"Â Low fuel.
"Â Fuel pressure regulator malfunction.
"Â Fuel injector malfunction.
"Â Fuel pump malfunction.
"Â ECT sensor malfunction.
"Â MAF sensor malfunction.
"Â HO2S malfunction.
"Â Purge solenoid malfunction.
"Â Inlet air leak.
"Â PCM malfunction.
"Â Open or short circuit between fuel injector and PCM connector C249 terminals No. 11 and No. 12.
"Â IAT sensor malfunction.
"Â EGR pressure sensor malfunction.
"Â PCV malfunction.

1. Ensure no air leaks in engine inlet system.

2. Check fuel pressure. If fuel pressure is okay, go to step 5). If fuel pressure is not within specifications, go to next step.

3. Check maximum pressure.

4. Check fuel pressure regulator.

5. Check fuel injectors. If injectors are okay, go to next step. If injector(s) is bad, replace injector(s).

6. Check ECT sensor. If ECT sensor is okay, go to next step. If ECT sensor is bad, replace ECT sensor.

7. Check MAF sensor. If MAF sensor is okay, go to next step. If MAF sensor is bad, replace MAF sensor.

8. Check TPS. If TPS is okay, go to next step. If TPS is bad, replace TPS.

9. 1.6L only, 1.8L go to next step. Check closed throttle position switch. Adjust as needed. If switch is okay, go to next step. If switch is bad, replace TPS.

10. Check IAT sensor. If IAT sensor is okay, go to next step. If IAT sensor is bad, replace IAT sensor.

11. Check EGR pressure sensor (1.6L) or EGR boost sensor(1.8L). If EGR pressure or boost sensor is okay, go to next step. If EGR pressure or boost sensor is bad, replace sensor.

12. Check purge solenoid. If purge solenoid is okay, go to next step. If purge solenoid is bad, replace purge solenoid.

13. Check PCV valve. Replace as needed.

14. Clear code. Recheck codes. If code returns, replace PCM. If code does not return, problem
is intermittent.