6E–414
4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Step
Action
Value(s)
Yes
No
10
Remove the MAF & IAT sensor assembly and check for the following conditions.
—
Verify repair
Go to Step 11
• Check for any accessory parts which may cause electric interference. If a problem is found, repair as necessary. Was a problem found?
—
Verify repair
Go to Step 12
Substitute a known good MAF & IAT sensor assembly and recheck. Was the problem solved?
—
Go to Step 13
Go to Step 21
Replace the MAF & IAT sensor assembly. Is the action complete?
—
Verify repair
—
—
Go to Step 20
Go to Step 15
• Objects blocking at the MAF sensor element. If a problem is found, repair as necessary. Was the problem found? 11
Check the MAF sensor harness for the following conditions. • Check for poor connector connection. • Check for misrouted harness.
12
13 14
1. Using the Tech 2 and ignition “On” and engine “Run”. 2. Monitor the following parameters in the data display. • “Desired Injection Quantity” & “Injection Quantity” • “Desired Injection Start” & “Actual Injection Start” Are the large gap or unstable parameter displayed between “Desired” and “Actual”? When idling or part-throttle
When accelerated
Desired
Desired
High
High
Actual Actual Low
Low Time
Time