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P1200







P1200 MULTIPLE INJECTOR FAILURE DETECTED





For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
With the engine running.

- Set Condition:
The ECM detects multiple Injector failures from one or more cylinders.





Diagnostic Test

1. CHECK FOR 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.

With the scan tool, erase ECM DTCs.
Test drive the vehicle and attempt to duplicate the problem.
With the scan tool, read ECM DTC's.
Did this DTC set again?

Yes

- Go To2

No

- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.Intermittent Condition

2. INJECTOR QUANTITY ADJUSTMENT

NOTE: Each Fuel Injector is labeled with a code. This code determines the injector quantity adjustment. Each Injector code must be programmed into the ECM using the scan tool.

Turn the ignition off.
Refer to the service information to locate each fuel injector label and check for the correct code for each fuel injector in the ECM.
Are all of the injector codes correct?

Yes

- Go To 3

No

- Using the scan tool, program the correct Fuel Injector code into the ECM.
- Perform the ECM Verification Test Ver. 1. Verification Tests.

3. CYLINDER FUEL QUANTITY CORRECTION
With the scan tool, perform the Cylinder Fuel Quantity Correction Test.
Is each Cylinder within specifications?

Yes

- Go To4

No

- Repair or replace as necessary.
- Perform the ECM Verification Test Ver. 1 Verification Tests.

4. FUEL INJECTOR HIGH-SIDE CONTROL CIRCUIT SHORTED TO VOLTAGE
Turn the ignition off.
Disconnect each Fuel Injector harness connector.
Disconnect the Engine Control Module (ECM) harness connector.
Remove the ASD Relay from the PDC.
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 in each Fuel Injector harness connector.
Is there voltage present on any of the High-Side Control circuits?

Yes

- Repair the appropriate Fuel Injector High-Side Control circuit(s) that had voltage present for a short to voltage.
- Perform the ECM Verification Test Ver. 1. Verification Tests.

No

- Go to 5

5. FUEL INJECTOR LOW-SIDE CONTROL CIRCUIT SHORTED TO VOLTAGE
NOTE: The jumper wire should still be in place.

Measure the voltage of each Fuel Injector Low-Side Control circuit in each Fuel Injector harness connector.
Is there voltage present on any of the Low-Side Control circuits?

Yes

- Repair the appropriate Fuel Injector Low-Side Control circuit(s) that had voltage present for a short to voltage.
- Perform the ECM Verification Test Ver. 1. Verification Tests.

No

- Go to 6

6. FUEL INJECTOR HIGH-SIDE 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 circuit in each Fuel Injector harness connector.
Is the resistance above 1000 ohms for each Fuel Injector High-Side Control circuits?

Yes

- Go to 7

No

- Repair the appropriate Fuel Injector High-Side Control circuit(s) that measured below 1000 ohms for a short to ground.
- Perform the ECM Verification Test Ver. 1. Verification Tests.

7. FUEL INJECTOR LOW-SIDE CONTROL CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and each Fuel Injector Low-Side Control circuit in each Fuel Injector harness connector.
Is the resistance above 1000 ohms for each Fuel Injector Low-Side Control circuits?

Yes

- Go to 8

No

- Repair the appropriate Fuel Injector Low-Side Control circuit(s) that measured below 1000 ohms for a short to ground.
- Perform the ECM Verification Test Ver. 1. Verification Tests.

8. FUEL INJECTOR HIGH-SIDE CONTROL CIRCUIT SHORTED TO FUEL INJECTOR LOW-SIDE CONTROL CIRCUIT
Measure the resistance between each Fuel Injector High-Side Control circuit and each Fuel Injector Low-Side Control circuit in each Fuel Injector harness connector.
Is the resistance above 1000 ohms for each Fuel Injector?

Yes

- Go to 9

No

- Repair the appropriate Fuel Injector High-Side Control circuit(s) that measured below 1000 ohms for a short to the Fuel Injector Low-Side Control circuit.
- Perform the ECM Verification Test Ver. 1. Verification Tests.

9. FUEL INJECTOR HIGH-SIDE CONTROL CIRCUIT OPEN OR HIGH RESISTANCE
Measure the resistance of each Fuel Injector High-Side Control circuit between each Fuel Injector harness connector and the Engine Control Module (ECM) harness connector.
Is the resistance below 10.0 ohms for each Fuel Injector High-Side Control circuit?

Yes

- Go to 10

No

- Repair the appropriate Fuel Injector High-Side Control circuit(s) that measured above 10.0 ohms for an open circuit or high resistance.
- Perform the ECM Verification Test Ver. 1. Verification Tests.

10. FUEL INJECTOR LOW-SIDE CONTROL CIRCUIT OPEN OR HIGH RESISTANCE
Measure the resistance of each Fuel Injector Low-Side Control circuit between each Fuel Injector harness connector and the Engine Control Module (ECM) harness connector.
Is the resistance below 10.0 ohms for each Fuel Injector Low-Side Control circuit?

Yes

- Go to 11

No

- Repair the appropriate Fuel Injector Low-Side Control circuit(s) that measured above 10.0 ohms for an open circuit or high resistance.
- Perform the ECM Verification Test Ver. 1. Verification Tests.

11. FUEL INJECTOR
Measure the resistance between the terminals of each Fuel Injector.
Is the resistance approximately 185k ohms (+/- 10%) for each Injector?

Yes

- Go to 12

No

- Replace appropriate Fuel Injector(s) that measured incorrectly.
- Perform the ECM Verification Test Ver. 1. Verification Tests.

12. ENGINE CONTROL MODULE (ECM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between each Fuel Injector and the Engine Control Module (ECM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
Look for the data to change or for the DTC to reset during the wiggle test.
Search for any Technical Service Bulletins that may apply.
Were any problems found?

Yes

- Repair as necessary.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Replace the Engine Control Module (ECM).
- Perform the ECM Verification Test Ver. 1. Verification Tests
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