Engine Electrical System
Troubleshooting
In this manual: Engine Electrical System
~2min read
Troubleshooting
Ignition System| Symptom | Suspected Area | Remedy |
| Vehicle shows Ready on the instrument panel, but the engine does not start on request from the HPCU (HEV Module). | Ignition Coil | Inspect the ignition coil or replace if necessary. |
| Spark Plugs | Inspect the spark plugs or replace if necessary. | |
| Ignition wiring is disconnected or damaged. | Repair the wiring or replace if necessary. | |
| Rough idle | Ignition Wiring | Repair the wiring or replace if necessary. |
| Ignition Coil | Inspect the ignition coil or replace if necessary. | |
| Engine shakes / poor acceleration | Spark plugs and spark plug cables | Inspect spark plugs / cable or replace if necessary |
| Ignition Wiring | Repair the wiring or replace if necessary. | |
| Poor mileage | Spark plugs and spark plug cables | Inspect spark plugs / cable or replace if necessary |
Charging System
| Symptom | Suspected Area | Remedy |
| Charging warning light does not illuminate when the Start/Stop button is on and the hybrid system is off. | Blown fuse | Check fuses |
| Bulb burnt out | Replace bulb | |
| Loose wiring connection | Tighten loose connection | |
| HPCU problem | Check the LDC. Refer to Group HC |
|
| Charging warning light does not turn off when the hybrid system is on. (Battery requires frequent recharging) | Battery cable loose, corroded or worn | Inspect cable connection, repair or replace cable |
| HPCU problem | Check the LDC. Refer to Group HC |
|
| Wiring | Repair or replace wiring | |
| Overcharging | HPCU problem | Check the LDC. Refer to Group HC |
| Voltage sensor wire | Repair or replace wiring | |
| Dismiss | Wiring connection loose or short circuit | Check wiring connection, repair or replace wiring |
| HPCU problem | Check the LDC. Refer to Group HC |
|
| Poor ground | Inspect ground or repair | |
| Worn battery | Replace battery | |
| Abnormal parasitic draw from the vehicle | Connect a current probe to measure current. It should be less than 0.05 A (50 mA) after the hybrid system is turned off and 10 minutes have elapsed. Make sure the luggage compartment lamp is off during this test. |
Starting System
| Symptom | Suspected Area | Remedy |
| Vehicle will not show Ready on the instrument panel when the hybrid system is on. | Low 12 V auxiliary battery charge | Charge or replace the 12 V auxiliary battery. |
| 12 V auxiliary battery cables are loose, corroded, or worn. | Repair or replace cables | |
| Transmission range switch (for vehicles with automatic transmission only) | Refer to Group AT - Automatic Transmission. | |
| Blown fuse | Replace fuse | |
| Ignition switch malfunction | Replace |
Test yourself
A quick Kia Optima Hybrid Owner's Manual quiz: every answer comes with an explanation and a link to the manual page.
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