The ignition system utilizes an individual module/coil for each spark plug. The following 4 circuits support each ignition module/coil assembly:
• | The ignition 1 voltage circuit |
• | The ground circuit |
• | The ignition control (IC) circuit |
• | The low reference circuit |
Each ignition module/coil connects directly to its spark plug through a wire spring conductor internal to the spark plug boot. The IC circuits transmit timing pulses from the powertrain control module (PCM) to each ignition module/coil assembles in the proper sequence for the spark plug firing event. The PCM monitors each IC circuit for improper voltage levels. If an improper voltage level is detected on an IC circuit, a DTC will set.
• | This electronic ignition (EI) system diagnostic table assumes that the vehicle battery is fully charged. Refer to Battery Inspection/Test in Engine Electrical. |
• | Other electrical, fuel, or mechanical conditions can cause an engine to crank but does not run, or set a DTC P0300 misfire code. |
• | An ignition coil, boots, or spark plugs may misfire only when moisture is present. Although difficult to test on this engine, selectively wetting down parts of the ignition system and monitoring for a misfire may help in isolating an intermittent condition. Replace any worn or torn spark plug boots or seals. |
• | If the ODD INJ or EVEN INJ fuse opens, this will also result in the loss of ignition 1 voltage to the odd or even ignition coils. |
Step | Action | Values | Yes | No | ||||||
---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views and Engine Controls Connector End Views | ||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | ||||||
2 | Attempt to start the engine. Does the engine start and run? | -- | Go to Step 21 | Go to Step 3 | ||||||
3 |
Does the test lamp illuminate on either test point of the fuse? | -- | Go to Step 32 | Go to Step 4 | ||||||
4 |
Does the test lamp illuminate on both test points of the fuse? | -- | Go to Step 11 | Go to Step 5 | ||||||
5 | Does the test lamp illuminate on one test point of the COIL/MDL fuse? | -- | Go to Step 6 | Go to Step 40 | ||||||
6 |
Does the MDL/COIL fuse open? | -- | Go to Step 33 | Go to Step 7 | ||||||
7 |
Does the MDL/COIL fuse open? | -- | Go to Step 34 | Go to Step 8 | ||||||
8 |
Does the MDL/COIL fuse open? | -- | Go to Step 34 | Go to Step 9 | ||||||
9 |
Does the MDL/COIL fuse open when an ignition module/coil assembly is connected? | -- | Go to Step 41 | Go to Step 10 | ||||||
10 |
Does the MDL/COIL fuse open when an ignition module/coil assembly is connected? | -- | Go to Step 41 | Go to Intermittent Conditions | ||||||
11 |
Does the test lamp illuminate? | -- | Go to Step 13 | Go to Step 12 | ||||||
12 |
Does the resistance measure greater than the specified value? | 2 ohms | Go to Step 36 | Go to Step 40 | ||||||
13 |
Does the resistance measure greater than the specified value? | 2 ohms | Go to Step 35 | Go to Step 14 | ||||||
14 |
Does the test lamp illuminate? | -- | Go to Step 16 | Go to Step 15 | ||||||
15 |
Does the resistance measure greater than the specified value? | 2 ohms | Go to Step 36 | Go to Step 40 | ||||||
16 |
Does the resistance measure greater than the specified value? | 2 ohms | Go to Step 35 | Go to Step 17 | ||||||
17 | Measure the resistance of the ground circuit from each ignition module/coil electrical connector on bank 1 to a good engine ground with a DMM. Does the resistance measure more than the specified value from each ignition module/coil electrical connector? | 2 ohms | Go to Step 38 | Go to Step 18 | ||||||
18 | Measure the resistance of the ground circuit from each ignition module/coil electrical connector on bank 2 to a good engine ground with a DMM. Does the resistance measure more than the specified value from each ignition module/coil electrical connector? | 2 ohms | Go to Step 38 | Go to Step 19 | ||||||
19 |
Does the resistance measure greater than the specified value? | 2 ohms | Go to Step 39 | Go to Step 20 | ||||||
20 | Measure the resistance of the IC low reference circuit on bank 2 from each ignition module/coil electrical connector to the PCM electrical connectors. Does the resistance measure greater than the specified value? | 2 ohms | Go to Step 39 | Go to Intermittent Conditions | ||||||
21 | Observe the misfire current counters with a scan tool. Does a cylinder or bank of cylinders indicate an increasing misfire count? | -- | Go to Step 22 | Go to Diagnostic Aids | ||||||
22 |
Does the resistance measure greater than the specified value? | 2 ohms | Go to Step 37 | Go to Step 23 | ||||||
23 | Measure the resistance of the ignition 1 voltage bus bar circuit of the underhood fuse block for a high resistance or for an open with a DMM. Does the resistance measure greater than the specified value? | 2 ohms | Go to Step 40 | Go to Step 24 | ||||||
24 | Measure the resistance of the ground circuit from the ignition module/coil electrical connector of the affected cylinder to a good ground with a DMM. Does the resistance measure greater than the specified value? | 2 ohms | Go to Step 38 | Go to Step 25 | ||||||
25 |
Does the resistance measure greater than the specified value on either circuit? | 5 ohms | Go to Step 39 | Go to Step 26 | ||||||
26 |
Did you find a condition? | -- | Go to Step 43 | Go to Step 27 | ||||||
27 | Remove the spark plug for the cylinder that was identified as causing a misfire. Refer to Spark Plug Replacement . Does the spark plug indicate oil contamination? | -- | Go to Base Engine Misfire with Excessive Oil Consumption in Engine Mechanical | Go to Step 28 | ||||||
28 | Does the spark plug indicate coolant contamination? | -- | Go to Base Engine Misfire with Coolant Consumption in Engine Mechanical | Go to Step 29 | ||||||
29 |
Does the misfire move with the spark plug exchange? | -- | Go to Step 42 | Go to Step 30 | ||||||
30 |
Does the misfire move with the ignition module/coil exchange? | -- | Go to Step 41 | Go to Step 31 | ||||||
31 | Test for an intermittent and for a poor connection at the ignition module/coil electrical connector. 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 43 | Go to Base Engine Misfire without Internal Engine Noises in Engine Mechanical | ||||||
32 | Repair the short to battery positive voltage in the ignition 1 voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 43 | -- | ||||||
33 | Repair the short to ground in the ignition 1 voltage circuit between the underhood junction block and either bank 1 or bank 2, 7-way electrical connector. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 43 | -- | ||||||
34 | Repair the short to ground in the ignition 1 voltage circuit between the 7-way electrical connector and the ignition module/coils. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 43 | -- | ||||||
35 | Repair the high resistance or an open in the ignition 1 voltage circuit between the 7-way electrical connector and the ignition module/coils. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 43 | -- | ||||||
36 | Repair the high resistance or an open in the ignition 1 voltage circuit between the underhood fuse block electrical connector and the 7-way electrical connector. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 43 | -- | ||||||
37 | Repair the high resistance or an open in the ignition 1 voltage circuit between the underhood fuse block electrical connector and the ignition module/coil electrical connectors. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 43 | -- | ||||||
38 | Repair the high resistance or an open in the ground circuit for the ignition module/coil assembly. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 43 | -- | ||||||
39 | Repair the high resistance or an open in the IC low reference circuit or the IC control circuit between the ignition module/coil assembly and the PCM. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 43 | -- | ||||||
40 | Replace the underhood fuse block. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Did you complete the replacement? | -- | Go to Step 43 | -- | ||||||
41 | Replace the ignition module/coil assembly. Refer to Ignition Coil Replacement - Bank 1 . Did you complete the replacement? | -- | Go to Step 43 | -- | ||||||
42 | Replace the spark plug. Refer to Spark Plug Replacement . Did you complete the replacement? | -- | Go to Step 43 | -- | ||||||
43 | Were you sent to this diagnostic table from the Engine Cranks but Does Not Run diagnostic table? | -- | Go to Step 45 | Go to Step 44 | ||||||
44 | Were you sent to this diagnostic table from the DTC P0300 diagnostic table? | -- | Go to Step 46 | -- | ||||||
45 |
Does the engine start and run? | -- | Go to Step 47 | |||||||
46 |
Did the DTC fail during this ignition cycle? | -- | Go to DTC P0300 | Go to Step 47 | ||||||
47 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |