The Trigger 1 Error Counter will increment by one every time the ECU counts an incorrect number of teeth on the Trigger 1 signal. The teeth are counted over 720 degrees of crankshaft rotation.
There are many reasons why the ECU could incorrectly count the number of teeth on Trigger 1 or Trigger 2. These include:
·Incorrect number of teeth specified in multi-tooth or multi-tooth / missing trigger modes.
·Incorrect Trigger 2 sync mode selected.
·Trigger wheel or trigger sensor mechanically moving due to engine vibration or cam-belt stretch.
·Incorrect wiring of crank or cam position sensors.
·Electrical interference.
·Incorrect trigger wheel design.
·Trigger arming voltages incorrect.
·Trigger sensor becoming saturated due to engine speed and number of trigger teeth.
Because some trigger setups rely on Trigger 1 and Trigger 2 for the ECU to know the degrees of crankshaft rotation it is possible that a problem with Trigger 2 could cause the Trigger 1 Error Counter to increment. The following examples will help demonstrate how the Trigger 1 Error Counter could increment.
Trigger setup:
Trigger Mode: Multi-Tooth / Missing Trigger 1 Multi-Tooth Posn: Crank Trigger 1 Tooth Count: 36 Trigger 1 Missing Teeth: 2 Trigger 2 Sync Mode: None
Under normal conditions on Trigger 1 the ECU would expect to see a gap of 2 teeth, then 34 teeth. The pattern would then be expected to repeat, and once the ECU had seen the trigger pattern twice it would know the crankshaft had rotated 720 degrees and know where in the engine cycle the engine is. The image below is a visual representation of what the ECU would normally expect to see.
 Trigger pattern with no problems
If however the ECU had seen one tooth more, or one tooth less than expected then it would increment the Trigger 1 Error Counter. The images below represent what the ECU would see when these faults occur.
 Trigger pattern with an extra tooth
 Trigger pattern missing a tooth |
Trigger setup:
Trigger Mode: Multi-Tooth Trigger 1 Multi-Tooth Posn: Crank Trigger 1 Tooth Count: 12 Trigger 2 Sync Mode: Cam Pulse 1x
Under normal conditions the ECU would expect to see one tooth on Trigger 2 and then 24 teeth on Trigger 1. Once the ECU had seen this trigger pattern it would know the crankshaft had rotated 720 degrees and know where in the engine cycle the engine is. The image below is a visual representation of what the ECU would normally expect to see.
 Trigger pattern with no problems
If however the ECU had seen one tooth more, or one tooth less than expected on either Trigger 1 or Trigger 2 then it would increment the Trigger 1 Error Counter. The images below represent what the ECU would see when these faults occur.
 Trigger pattern with an extra tooth on Trigger 1
 Trigger pattern with a missing tooth on Trigger 1
 Trigger pattern with an extra tooth on Trigger 2
 Trigger pattern with no tooth on Trigger 2 |
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