This engine is equipped with a distributorless ignition system called the Electronic Ignition (EI) system. The primary circuit of the EI system consists of the following items:
• | Two separate ignition coils |
• | Electronic Ignition Control Module (ICM) |
• | Crankshaft Position (CKP) sensor |
• | Related connecting wires and the ignition control portion of the PCM |
Each secondary circuit consists of the following items:
• | Secondary winding of the coil |
• | Two connecting metal strips that are molded into the coil housing |
• | Spark plug boot/connector assemblies |
• | Spark plugs |
• | A small amount of resistance in the battery positive voltage circuit to the PCM may cause a no start with a functioning MIL. Check the battery positive voltage circuit for excessive resistance or corrosion. |
• | Check the Throttle Position (TP) sensor for binding or sticking or for being intermittently shorted or open. |
• | If the THEFT SYSTEM telltale is flashing on the Instrument Panel Cluster (IPC), the theft deterrent system has been activated, refer to the DTC P1629 Theft Deterrent Fuel Enable Signal Not Received 2.4L, or the DTC P1629 Theft Deterrent Fuel Enable Signal Not Received 2.2L for further diagnosis. |
• | Check for water or foreign material in the fuel system. |
• | Check for a basic engine problem (low compression). |
• | Verify that only resistor spark plugs are used. |
• | A scan tool can be used to energize the fuel pump ON to check fuel pump operation and for ignition voltage at the fuel injector harness. |
Number(s) below refer to the step number(s) on the Diagnostic Table.
The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored in the scan tool for later reference.
Diagnosis of the DTCs that may be set could lead to the cause of the Cranks But Will Not Run condition.
The PCM grounds will only cause a problem if all the grounds are not making a good connection. If a PCM ground problem is suspected, the most probable place to check is where all the grounds meet at the engine block.
Locate and repair any shorts that may have caused the fuse to open before replacing the fuse.
A TP sensor that reads too high may cause an incorrect fueling condition (Clear flood enabled).
An engine that has not been started or recently started should display ECT and IAT temperatures that are relatively close to each other. During the warmer weather, the IAT readings maybe slightly higher than the ECT readings. If a malfunctioning coolant sensor is suspected, the spark plugs may have fouled out and need to be replaced to start the engine.
If the scan tool loses serial data only while cranking the engine, then the ignition switch is not sending voltage to the PCM while in the crank position.
This step looks for a normal barometer reading and a change in MAP sensor values while cranking the engine. This step verifies the MAP sensor can detect the change in the manifold pressure that occurs while cranking the engine. Compare any questionable barometer readings with readings from another vehicle. If a malfunctioning MAP sensor is suspected, the spark plugs mat have fouled out and need to be replaced.
While cranking the engine, the CKP Activity (7X reference should increment to 255, then rollover to 0.
Check for possible voltage loss to the PCM including the ignition switch itself.
The ignition positive voltage should be available at the ignition feed terminal (L) of the ICM 11 pin harness electrical connector, and the ground terminal (K) should be a good ground.
The CKP sensor core is a magnet and should be magnetized.
The CKP sensor should output a AC voltage near 1100-1300 mV as the crankshaft turns. It is possible to trigger the ICM with a voltage as low as 200 mV. If no voltage is produced, a poor CKP sensor electrical connection or a malfunctioning CKP sensor is indicated.
The test light connected to B+ simulates a reference signal to the PCM. A fuel injector test light can be installed and will blink for every other touch of the test light if the CKP Activity (7X reference) circuit, the PCM and the fuel injector driver circuits are all functioning properly.
If the test light illuminates while probing the CKP Activity (7X reference) circuit, then the CKP Activity (7X reference) circuit is shorted to ground. If the test light remains OFF and the CKP Activity Counter does not increment, then the CKP Activity (7X reference) circuit is open. If the CKP Activity Counter increment several counts, when the reference low (terminal H) is probed, then the CKP Activity (7X reference) is shorted to voltage.
Replacement PCMs must be reprogrammed and the crankshaft position system variation learn procedure must be performed. Refer to the latest Techline information for PCM programming and the CKP System Variation Learn Procedure for the Crankshaft Position System Variation Procedure.
Battery voltage should be available at the fuel injector ignition feed circuit whenever the fuel pump power feed circuit is switched ON and when the PCM is receiving ignition pulses, during engine cranking or when running. The ignition switch must be turned OFF for at least 10 seconds to assure that the PCM powers down and will then switch the fuel pump back ON for 2-3 seconds when the ignition switch is turned back ON.
By installing the spark plug jumper leads and testing for spark on all 4 plug wire leads (one at a time), each ignition coil(s) ability to produced at least 25,000 volts is verified.
The fuel pump is turned ON by the PCM for 2-3 seconds after ignition switch is first turned ON. This step checks to see if the fuel pump and fuel pump relay are operating correctly and if the fuel pressure is within the proper range. Refer to the Fuel System Diagnosis for fuel pressure gauge installation procedure.
This step verifies that the PCM is sending a signal to the Ignition Control Module (ICM) to fire the ignition coils. If the test light blinks, then the signal is OK to this point and the no spark condition lies in the ignition coil electrical harness or the ignition coil that did not produce spark.
The ignition coil electrical harness can easily be checked by performing the previous step with the ignition coil electrical harness connected to the ICM. Check for a voltage and ground signal to the ignition coils at the coil electrical connector.
Step | Action | Value(s) | Yes | No | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | |||||||||||||
Are DTCs P0601, P0602, P1629 set? | -- | Go to applicable DTC table | ||||||||||||
Inspect the PCM ground connection(s) at the engine block. Is the ground connection OK? | -- | |||||||||||||
4 | Inspect the following fuses:
Are the fuses OK? | -- | ||||||||||||
5 | Repair the PCM ground connection. Refer to Connector Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||||||||
6 |
Was it necessary to add fuel? | -- | ||||||||||||
Is the action complete? | -- | -- | ||||||||||||
Does the TP sensor read less then the specified value? | 1.0 V | Go to DTC P0123 Throttle Position (TP) Sensor Circuit High Voltage | ||||||||||||
Is the Engine Coolant Temperature (ECT) relatively close to the Intake Air Temperature (IAT)? | -- | Go to DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage or DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage | ||||||||||||
Crank the engine while watching the MAP sensor readings on the scan tool. Was serial data lost while cranking the engine? | 4.0 V | |||||||||||||
Does the MAP sensor read over the specified value and then change while cranking the engine? | 4.0 V | |||||||||||||
Check to see if the CKP Activity Counter increments while cranking the engine with the scan tool. Does the CKP Activity Counter increment while cranking? | -- | |||||||||||||
Repair the voltage loss to the PCM from the ignition switch. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | ||||||||||||
Does the DMM read the specified voltage? | B+ | |||||||||||||
15 |
Is the resistance reading within the specified value? | 500-900ohms | ||||||||||||
16 | Repair the poor electrical terminal connection or open in the following ICM circuit(s): Refer to Connector Repairs in Wiring Systems.
Is the action complete? | -- | -- | |||||||||||
17 |
Was a repair necessary? | -- | ||||||||||||
Is the CKP sensor magnetic with undamaged terminals and the resistance within the specified value? | 500-900ohms | |||||||||||||
Is the voltage reading greater than the specified value? | 200 mV | |||||||||||||
20 |
Is the action complete? | -- | ||||||||||||
Does the CKP Activity Counter increment one count as the test light touches the 7x Reference signal terminal (cavity G)? | -- | |||||||||||||
22 |
Is the action complete? | -- | -- | |||||||||||
23 | Replace the CKP sensor. Refer to the Crankshaft Position Sensor Replacement . Is the action complete? | -- | -- | |||||||||||
24 |
Was a repair necessary? | -- | ||||||||||||
Was a repair necessary? | -- | |||||||||||||
26 | Replace the ICM. Refer to the Ignition Control Module Replacement . Is the action complete? | -- | -- | |||||||||||
Is the action complete? | -- | -- | ||||||||||||
Does the test light blink? | -- | |||||||||||||
Does spark jump the spark tester on all 4 spark plug wires? | -- | |||||||||||||
Important: The ignition switch may have to be cycled more than one time to achieve the highest fuel pressure. Is the fuel pressure between the specified value? | 284-325 kPa (41-47 psi) | Go to Fuel System Diagnosis | ||||||||||||
31 |
Was any spark plug replacement necessary? | -- | Go to Diagnostic Aids | |||||||||||
32 |
Notice: Do not leave the test lamp connected to the PCM IC circuit connector for longer than 5 seconds at a time. Failure to do so may damage the ignition coil and/or the Ignition Control Module. Does a spark jump on the spark tester? | -- | ||||||||||||
Notice: Do not leave the test lamp connected to the PCM IC circuit connector for longer than 5 seconds at a time. Failure to do so may damage the ignition coil and/or the Ignition Control Module. Does the other test light blink? | -- | |||||||||||||
Was a repair necessary? | -- | |||||||||||||
35 | Replace the ignition coil that did not spark. Refer to the Ignition Coil Replacement . Is the action complete? | -- | -- | |||||||||||
36 |
Was a repair necessary? | -- | ||||||||||||
37 |
Does the engine start and continue to run? | -- | ||||||||||||
38 |
Are any DTCs displayed that have not been diagnosed? | -- | Go to Applicable DTC table | System OK |