Diagnostic Trouble Code (DTC) P0351

Ignition Control Circuit A Fault (Cylinder 1 & 4)

 

 

 

Circuit Know-how

 

  • A ground for the electronic spark timing A circuit is made by the ECM.
  •  The magnetic field set up by the coil dies the moment the ECM stops providing the ground path of the ignition primary coil.
  • Consequently the dying magnetic field generates a voltage in the secondary coil which shoots the spark plug.
  • The set-up between the ECM and the electronic ignition system ignition coil is controlled and supervised for an open circuit, short to voltage, and short to ground.
  •  A Diagnostic Trouble Code (DTC) P0351 will shoot up as soon as the ECM notices an error in the electronic spark timing A circuit.

 

 

When will DTC set?

 

Task boosted after DTC sets

When will DTC clear?

DTC sets when

1) There is an erroneous monitor fault feedback signal.

 

1) The Malfunction Indicator Lamp (MIL) will be seen to glow.

1) The MIL will go off after four consecutive ignition cycles where the diagnostic is found running faultlessly.

 

2) Ignition is in ON mode.

 

 

2) The ECM will begin to record operating conditions when the diagnostic fails.

2) A history DTC will automatically clear after 40 consecutive warm-up cycles faultlessly.

3)  Fault flag increments fail to be counted.

3) This data will be stored in the Freeze Frame and Failure Records will be boosted.

3) The Scan Tool can be used to unset all DTCs.

4)  There has to be more than 200 failures within 255 test cycles (SOHC).

4) A history DTC is stored.

4)  If the ECM battery feed is de-linked for more than 10 seconds.

5)  There has to be more than 20 failures within 40 test cycles (DOHC).

5)  Low speed coolant fan turns on.

 

-

 

 

 

 

Diagnostic Tools

 

 

It might so happen that an intermittent may be caused due to an ill connection, rubbed-through wire insulation or a wire broken inside the insulation. In that case you need to look out for the following:


1.       An ill connection - Examine the ECM harness and connectors for faulty mating, broken locks, wrongly formed or tampered terminals, and poor terminal-to-wire connections.

 

2.      Tampered harness - Examine the wiring harness to see if there is any damage. If you see that the harness is perfect, then de-link the ECM, switch ON the ignition and see if a voltmeter is connected to the 58X reference circuit at the ECM harness connector as you move the connectors and the wiring harnesses linked to the ECM. A fluctuation in the voltage will indicate the location of the fault.

 

3.      If a review of the Failure Records vehicle mileage is conducted at the time the diagnostic test failed will enable to note the frequency of the condition that caused the DTC to be set occurs. This is likely to help in diagnosing the condition.

 

 

HOW TO UNSET A DTC

DTC P0351 - Ignition Control Circuit A Fault (Cylinder 1 and 4)

 

 

Step

Task

Positive

Negative

1

Run an EOBD System check.

 

Task Done?

Follow Step 2

Follow

"On-Board Diagnostic System Check"

2

1)       See whether there is any faulty connection or a tampered terminal C at the Electronic Ignition (EI) system ignition coil.

2)       If so then correct it suitably.

 

       Job over?

Follow Step 8

Follow Step 3

3

1)       Repeat task 1 of step 2 at terminal M51/M35 at the ECM.

2)       If any discrepancy is detected then correct it suitably.

 

Work Done?

 

Follow Step 8

Follow Step 4

4

  1. Switch OFF the ignition.
  2. De-link the ECM connector.
  3. Look up the ignition control circuit for a short to ground.
  4. Correct accordingly.

Task accomplished?

 

 

Follow Step 8

Follow Step 5

5

1)       Now look up the ignition control circuit for a short to voltage.

2)       Correct accordingly.

 

 

Job Done?

 

Follow Step 8

Follow Step 6

6

3)       Now look up the ignition and verify if there is an open ignition control circuit.

4)       Work to correct it suitably.

 

 

Job complete?

Follow Step 8

Follow Step 7

7

  1. Switch OFF the ignition.
  2. Substitute the ECM.

Task accomplished?

 

Follow Step 8

-

8

  1. Unset all DTCs using a Scan Tool.
  2. After starting the engine leave it to idle at normal operating temperature.
  3. Regulate the vehicle within the Conditions for setting this DTC as specified in the supporting text.

Do you see that the scan tool reads that this diagnostic has been run and passed?

Follow Step 9

Follow Step 2

9

Inspect to see if there is any additional DTCs set.

 

Do you see any DTCs displayed that have not been diagnosed?

 

Follow applicable DTC table

The System of your car is just fine.