Troubleshooting

Table 48
Diagnostic Trouble Codes for Low Intake Manifold Air Pressure
J1939 Code
Description
Notes
1127-18 Engine Turbocharger 1 Boost Pressure : Low
- moderate severity (2)
The Electronic Control Module (ECM) detects the following conditions:
The actual intake manifold air pressure is less than the desired intake manifold
air pressure for at least 10 seconds. The difference between the two values is
dependent on engine operating conditions.
The engine speed is between 1000 rpm and 4000 rpm.
The engine coolant temperature is greater than 45° C (113° F).
There are no active 102 diagnostic codes for the intake manifold air pressure
sensor.
An active regeneration is not in progress.
There are no other active engine derates.
If equipped, the warning lamp will flash. The engine will be derated.
The fault will be cleared when the intake manifold air pressure is within the ac-
ceptable range for at least 11 minutes.
Probable Causes
• Intake air filter
• Air intake system
• Wastegate regulator
• Turbocharger
Recommended Actions
Note: The procedures have been listed in order of
probability. Complete the procedures in order.
Table 49
Troubleshooting Test Steps
Values Results
1. Intake Air Filter
A. Check the air filter restriction indicator, if equipped.
B. Ensure that the air filter is clean and serviceable.
Air filter Result: The air filter is blocked.
Repair: Replace the air filter element. Refer to the Operation
and Maintenance Manual, “Engine Air Cleaner Element -
Replace”.
Result: The air filter is OK.
Proceed to Test Step 2.
2. Air Intake System
A. Check the air intake system for the following defects:
· Blockages
· Restrictions
· Damage to the air intake ducts and hoses
· Loose connections and air leaks
Air intake Result: The air intake system is blocked, restricted, damaged,
or loose.
Repair: Make all necessary repairs to the air intake system.
Result: The air intake system is OK.
Proceed to Test Step 3.
(continued)
UENR0612-07 105
Symptom Troubleshooting
This document has been printed from SPI2. NOT FOR RESALE