P0268 Jeep OBD Code Definition
FUEL INJECTOR 3 CIRCUIT HIGH
For a complete wiring diagram Refer to Section 8W
- When Monitored:
With the engine cranking or running.
- Set Condition:The ECM detects a fault on a Fuel Injector Control circuit.
| Possible Causes |
| ENGINE CONTROL MODULE |
| INTERMITTENT CONDITION |
| FUEL INJECTOR CONTROL CIRCUIT SHORTED TO VOLTAGE |
| FUEL INJECTOR CONTROL CIRCUIT SHORTED TO GROUND |
| FUEL INJECTOR CIRCUITS SHORTED TOGETHER |
| FUEL INJECTOR CONTROL CIRCUIT OPEN |
| FUEL INJECTOR |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
(Refer to 9 – ENGINE – DIAGNOSIS AND TESTING)
Diagnostic Test
1. VERIFY ACTIVE DTC
NOTE:
If the ECM detects and stores a DTC, the ECM also stores the engine/vehicle operating conditions under which the DTC was set. Some of these conditions are displayed
on the scan tool at the same time the DTC is displayed.
NOTE:
Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
With the scan tool, erase the ECM DTCs.
Attempt to start the engine and test drive the vehicle.
With the scan tool, read the ECM DTCs.
Did this DTC set again?
Yes
- Go To 2
No
- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.
(Refer to 9 – ENGINE – DIAGNOSIS
AND TESTING)
2. CHECKING FOR OTHER DTCS
NOTE:
An open ASD power supply to the ECM will cause multiple DTC’s including this DTC to set.
NOTE:
Check the ECM for other DTC’s. If other DTC’s are set with this DTC refer to the symptom list and perform the CHECKING THE ECM POWER AND GROUND CIRCUITS test before
continuing.
If the ECM power and ground circuits are functioning properly continue with this test.
Yes
- Go To 3
3. FUEL INJECTOR CONTROL CIRCUIT SHORTED TO VOLTAGE
Turn the ignition off.
Disconnect all of the Cylinder Fuel Injector harness connectors.
Disconnect the ECM harness connectors.
Remove the ASD Relay from the TIPM.
Connect a jumper wire between cavity 30 and cavity 87 of the ASD Relay connector.
Turn the ignition on.
Measure the voltage of each Fuel Injector High-Side Control circuit.
Measure the voltage of each Fuel Injector Low-Side Control circuit.
Is the voltage above 1.0 volt for any of the measurements?
Yes
- Repair the appropriate Fuel Injector Control circuit for a short to voltage.
- Perform the ECM Verification Test Ver. 1.(Refer to 9 – ENGINE – STANDARD PROCEDURE)
No
- Go To 4
4. FUEL INJECTOR CONTROL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Remove the jumper wire and install the ASD Relay.
Measure the resistance between ground and each Fuel Injector High-Side Control circuits.
Measure the resistance between ground and each Fuel Injector Low-Side Control circuits.
Is the resistance below 1000 ohms for any of the measurements?
Yes
- Repair the Fuel Injector Control circuit for a short to ground.
- Perform the ECM Verification Test Ver. 1.(Refer to 9 – ENGINE – STANDARD PROCEDURE)
No
- Go To 5
5. FUEL INJECTOR CIRCUITS SHORTED TOGETHER
Measure the resistance between each of the Fuel Injector High-Side Control circuits and the Fuel Injector Low-Side Control circuits.
Is the resistance below 1000 ohms for any of the measurements?
Yes
- Repair the Fuel Injector circuits that measured below 1000 ohms for a short together.
- Perform the ECM Verification Test Ver. 1.(Refer to 9 – ENGINE – STANDARD PROCEDURE)
No
- Go To 6
6. FUEL INJECTOR CONTROL CIRCUIT OPEN
Measure the resistance of each Fuel Injector High-Side and Low-Side Control circuits between its respective injector harness connector and the ECM harness connector.
Is the resistance below 10.0 ohms for each measurement?
Yes
- Go To 7
No
- Repair the appropriate Fuel Injector Control circuit for an open.
- Perform the ECM Verification Test Ver. 1.(Refer to 9 – ENGINE – STANDARD PROCEDURE)
7. FUEL INJECTOR INTERNAL SHORT TO GROUND
Measure the resistance between either terminal of each Fuel Injector and ground.
Is the resistance above 500k ohms for each measurement?
Yes
- 8
- Perform the ECM Verification Test Ver. 1.(Refer to 9 – ENGINE – STANDARD PROCEDURE)
No
- Replace the Fuel Injector that did not measure above 500k ohms to ground.
- Perform the ECM Verification Test Ver. 1.(Refer to 9 – ENGINE – STANDARD PROCEDURE)
8. CHECK CYLINDER FUEL INJECTOR RESISTANCE
Measure the resistance of each Fuel Injector (measure across both terminals of the injector).
Is the resistance 185k ohms (+/- 10%)?
Yes
- Go To 9
- Perform the ECM Verification Test Ver. 1.(Refer to 9 – ENGINE – STANDARD PROCEDURE)
No
- Replace the Fuel Injector that did not measure 185K ohms (+/- 10%).
- Perform the ECM Verification Test Ver. 1.(Refer to 9 – ENGINE – STANDARD PROCEDURE)
9. MULTIPLE CYLINDER FUEL INJECTOR DTC’S
Were there multiple Cylinder Fuel Injector DTC’s set in the ECM?
Yes
- 10
- Perform the ECM Verification Test Ver. 1.(Refer to 9 – ENGINE – STANDARD PROCEDURE)
No
- Replace the Cylinder Fuel Injector 3.
- Perform the ECM Verification Test Ver. 1.(Refer to 9 – ENGINE – STANDARD PROCEDURE)
10. CYLINDER FUEL INJECTOR
Reconnect all harness connectors.
Turn the ignition on.
With the scan tool, clear all ECM DTC’s.
Disconnect the Cylinder 1 Fuel Injector harness connector.
With the scan tool, read the ECM DTC’s.
NOTE:
The continuing setting of multiple DTC’s indicates that the disconnected injector is not the cause of these faults.
NOTE:
If multiple DTC’s did not reset after disconnecting a single injector, replace the injector that was disconnected. In this case the lack of multiple DTC’s setting indicates
that the disconnected injector is the cause of these faults.
Choose the correct result below.
The ECM set multiple Cylinder Injector DTC’s.
- Reconnect the disconnected Injector harness connector and repeat test by disconnecting another injector until multiple
DTC’s are not set.
- Perform the ECM Verification Test Ver. 1.(Refer to 9 – ENGINE – STANDARD PROCEDURE)
The ECM set only a DTC for the disconnected Cylinder Injector
- Replace the Cylinder Fuel Injector that was disconnected.
- Perform the ECM Verification Test Ver. 1.(Refer to 9 – ENGINE – STANDARD PROCEDURE)