Test Description

WARNING: This page is about a different car, the 2004 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

The number below refers to the step number on the diagnostic table.

4: Monitoring the misfire current counters determines if a fault is present.

Electronic Ignition (EI) System Diagnosis

Step	Action	Value(s)	Yes	No
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) Connector End Views or Engine Controls 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	Crank the engine. Observe the engine speed parameter with a scan tool. Does the scan tool display engine RPM?	-	Go to Step 3	Go to Step 13
3	Is DTC P0335, P0336, or P0351-P0358 also set?	-	Go to Diagnostic Trouble Code (DTC) List	Go to Step 4
4	Idle the engine. Observe the misfire current counters on the scan tool. Does the scan tool display any misfire current counters incrementing?	-	Go to Step 5	Go to Intermittent Conditions
5	Turn OFF the ignition. Remove the fuel pump relay. Test for spark at each affected cylinder with the J 26792 Spark Tester. Do you have bright blue spark on the cylinders?	-	Go to Step 6	Go to Step 7
6	Remove the spark plugs. Inspect the spark plugs for any abnormal conditions or damage. Refer to Spark Plug Inspection . Are the spark plugs in good condition?	-	System OK	Go to Step 22
7	Measure the spark plug wire resistance. Refer to Spark Plug Wire Inspection . Is the resistance more than the specified value?	700 ohm/ft	Go to Step 23	Go to Step 8
8	Turn OFF the ignition. Disconnect the affected ignition coil. Turn ON the ignition, with the engine OFF. Probe the ignition voltage circuit of the affected ignition coil with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate?	-	Go to Step 9	Go to Step 19
9	Probe the ignition voltage circuit at the affected ignition coil with a test lamp that is connected to the ground circuit of the affected ignition coil. Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate?	-	Go to Step 10	Go to Step 20
10	Probe the ignition voltage circuit at the affected ignition coil with a test lamp that is connected to the low reference circuit of the affected ignition coil. Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate?	-	Go to Step 11	Go to Step 15
11	Measure the resistance of the ignition voltage circuit of the affected ignition coil from the fuse that supplies ignition voltage to the affected ignition coil to the harness connector of the affected ignition coil. Is the resistance less than the specified value?	3 ohm	Go to Step 12	Go to Step 19
12	Measure the resistance of the ground circuit of the affected ignition coil from the harness connector of the affected ignition coil to a good ground. Is the resistance less than the specified value?	3 ohm	Go to Step 17	Go to Step 20
13	Turn ON the ignition, with the engine OFF. Disconnect the crankshaft position (CKP) sensor. Measure the voltage from the CKP sensor 12-volt reference circuit to a good ground with the DMM. Compare the measured voltage with the system voltage. Is the difference in the voltage more than the specified value?	0.5 V	Go to Step 14	Go to Step 16
14	Test for a short to ground in the CKP 12-volt reference circuit or the camshaft position (CMP) sensor 12-volt reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 26	Go to Step 18
15	Test the low reference circuit of the ignition coil for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 26	Go to Step 18
16	Test for shorted terminals and poor connections at the CKP sensor. 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 26	Go to Step 21
17	Test for an intermittent and for a poor connections at the ignition coil. 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 26	Go to Step 24
18	Test for shorted terminals and for poor connections at the powertrain control module (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 26	Go to Step 25
19	Repair the ignition voltage circuit of the affected ignition coil for one of the following conditions: An open High resistance A short to ground Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?	-	Go to Step 26	-
20	Repair the ground circuit of the affected ignition coil for one of the following conditions: An open High resistance Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?	-	Go to Step 26	-
21	Replace the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement . Did you complete the replacement?	-	Go to Step 26	-
22	Replace the spark plug. Refer to Spark Plug Replacement . Did you complete the replacement?	-	Go to Step 26	-
23	Replace the spark plug wire. Refer to Spark Plug Wire Replacement . Did you complete the replacement?	-	Go to Step 26	-
24	Replace the ignition coil. Refer to Ignition Coil(s) Replacement . Did you complete the replacement?	-	Go to Step 26	-
25	Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement . Did you complete the replacement?	-	Go to Step 26	-
26	Turn OFF the engine for 30 seconds. Start the engine and operate the vehicle. Observe the vehicle performance and driveability. Does the vehicle operate normally?	-	System OK	Go to Step 3