Diagnostic Aids

DTC P1374 can be caused by secondary components leaking high voltage into the IC module.

Inspect for the following conditions:

Incorrect harness routing near secondary ignition components
Ignition coil arcing to wiring harness or IC module-Inspect the ignition coils for the following conditions:
- Cracks
- Carbon tracking
- Other signs of damage
Secondary ignition wires arcing to the wiring harness
If the DTC is determined to be intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

DTC P1374

Step	Action	Yes	No
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views
1	Did you perform the Diagnostic System Check-Engine Controls?	Go to Step 2	Go to Diagnostic System Check - Engine Controls
2	Attempt to start the engine. Does the engine start and run?	Go to Step 4	Go to Step 3
3	Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data. Does the DTC fail this ignition?	Go to Step 4	Go to Diagnostic Aids
4	Turn OFF the ignition. Disconnect the 6-way ignition control module connector. Refer to Ignition Control Module Replacement . Remove the injector fuse. Turn ON the ignition, with the engine OFF. Momentarily probe the low resolution engine speed signal circuit at the ignition module harness connector with a test lamp connected to B+. Observe the Engine Speed parameter with a scan tool. Is an Engine Speed displayed?	Go to Step 8	Go to Step 5
5	Did the test lamp illuminate?	Go to Step 7	Go to Step 6
6	Turn OFF the ignition. Disconnect the powertrain control module (PCM). Refer to Powertrain Control Module (PCM) Replacement . Turn ON the ignition, with the engine OFF. Test the low resolution engine speed signal circuit of the ignition control module for the following conditions: An open A short to voltage High resistance Refer to Wiring Repairs and Circuit Testing in Wiring Systems. Did you find and correct the condition?	Go to Step 12	Go to Step 9
7	Turn OFF the ignition. Disconnect the PCM. Refer to Powertrain Control Module (PCM) Replacement . Test the low resolution engine speed signal circuit of the ignition control module for a short to ground or for high resistance. Refer to Wiring Repairs and Circuit Testing in Wiring Systems. Did you find and correct the condition?	Go to Step 12	Go to Step 9
8	Test for an intermittent and for a poor connection at the ignition control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 12	Go to Step 10
9	Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 12	Go to Step 11
10	Replace the ignition control module. Refer to Ignition Control Module Replacement . Did you complete the replacement?	Go to Step 12	-
11	Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement . Did you complete the replacement?	Go to Step 12	-
12	Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?	Go to Step 2	Go to Step 13
13	Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?	Go to Diagnostic Trouble Code (DTC) List	System OK