Extended Idling in Cold Ambient Temperatures Can Cause Diesel Particulate Filter (DPF) Regeneration Issues on Products Equipped with the Caterpillar Regeneration System (CRS){108F} Caterpillar

Articulated Truck:

735B (S/N: T4P1-UP)

740B (S/N: T4R1-UP)

740B EJECTOR (S/N: T4S1-UP)

Engine:

C13 (S/N: KWJ1-UP)

C15 (S/N: LDN1-UP)

C18 (S/N: BDN1-UP)

Industrial Engine:

C9.3 (S/N: C9N1-UP)

Excavator:

336E (S/N: YCE1-UP; YEP1-UP; CMR1-UP; BZY1-UP)

349E (S/N: DGE1-UP; TFG1-UP; KCN1-UP; KFX1-UP; MPZ1-UP)

568 (S/N: BRB1-UP; YJX1-UP)

Motor Grader:

12M Series 2 (S/N: F9B1-UP; F9M1-UP)

140M Series 2 (S/N: M9D1-UP; R9G1-UP; M9J1-UP; R9M1-UP)

160M Series 2 (S/N: M9E1-UP; M9K1-UP; R9L1-UP; R9T1-UP)

Mobile Hydraulic Power Unit:

336E MHPU (S/N: T3Z1-UP)

349E MHPU (S/N: S3P1-UP)

Track-Type Tractor:

D6T (S/N: KSB1-UP; ZJB1-UP; DTD1-UP; EJJ1-UP; SLJ1-UP; GMK1-UP; TSM1-UP; PLR1-UP; JRW1-UP; RCW1-UP)

D7E (S/N: TJA1-UP; TAN1-UP)

D8T (S/N: MLN1-UP; FCT1-UP)

Wheel Loader:

966K (S/N: PBG1-UP; TFS1-UP; NGX1-UP)

972K (S/N: PEM1-UP; Z4W1-UP)

980K (S/N: W7K1-UP; GTZ1-UP)

Wheel Tractor-Scraper:

621H (S/N: DBK1-UP)

623H (S/N: DBF1-UP)

627H (S/N: DBW1-UP)

Introduction

The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.

Problem

Caterpillar has discovered that when certain products equipped with the Caterpillar Regeneration System (CRS) are left idling for extended periods of time (greater than 1 hr) and ambient temps are lower than −15° C (5° F), certain conditions may be met which will disable the ability to regenerate the DPF. If the regeneration system cannot activate, the DPF will accumulate too much soot and must eventually be replaced.

The issues Caterpillar has identified in extreme cold ambient conditions are the coolant temperature may become too cold for the regeneration system to activate. Also, the pressure lines which connect the DPF inlet section to the DPF intake pressure sensor may collect condensation and freeze. This freezing causes an E1154 (2) or 3609-18 Low DPF #1 Intake Pressure event code. The event code will disable the regeneration until the fault condition goes away.

If you suspect low coolant temperature may be contributing to an inability to regenerate the DPF, review the product status report. The product status report is used for investigating the following fault code trend. If coolant temp is the only issue, you will likely see a combination of the following fault codes:

1. E995 (2) High DPF #1 Soot Loading or 3719-16 Particulate Trap #1 Soot Load Percent : High - moderate severity (2)
   • Indicates DPF soot load percent has reached 100 percent

2. E995(3) High DPF #1 soot loading or 3719-0 Particulate Trap #1 Soot Load Percent : High - most severe (3)
   • Indicates DPF soot load percent has reached 116 percent

3. E992(3) DPF Active Regeneration Inhibited Due to Temporary System Lockout or 3714-31 Particulate Trap Active Regeneration Inhibited Due to Temporary System Lockout
   • Indicates DPF soot load reached 116 percent and 10 minutes has passed since that point. Ability to perform automatic or manual regenerations is disabled. Caterpillar Electronic Technician (ET) regeneration is only type of regeneration allowed.

4. E991 (3) DPF Active Regeneration Inhibited Due to Permanent System Lockout or 3715-31 Particulate Trap Active Regeneration Inhibited Due to Permanent System Lockout
   • Indicates DPF soot load percent has reached 140 percent. All types of regeneration are disabled. DPF must be replaced as the amount of soot load will damage the DPF if ignited by regeneration process.

If you suspect the pressure line for the DPF intake pressure has frozen, you will see a combination of fault codes. These codes will consist of the codes listed above with the addition of the following codes: E1154 (2) DPF #1 intake pressure low and 3609-18 DPF #1 Intake Pressure : Low - moderate severity (2).

Solution

Caterpillar recommends the following when extended idling is likely to occur and ambient temperatures are less than −15° C (5° F):

• Turn off machine before the end of shift. Before shutting down, perform a manual DPF regeneration and reduce soot load to 0 percent. The soot load must be above the 15 percent threshold needed to activate a manual DPF regeneration.

If extended idling is a necessity or the customer is not willing to shut down the machine, perform the following. These items will help increase likelihood of successful regeneration during the idle event:

• Before leaving the machine unattended, make sure that coolant temperature is at normal operating temperature (typically between 80° C (176° F) to 90° C (194° F) for products listed in this publication). Also, perform a manual DPF regeneration and make sure that soot load is reduced to 0 percent. This regeneration will allow the longest opportunity before another regeneration is required.

• Leave engine speed at the programmed low idle speed. This will allow the cold engine elevated idle feature to work properly. If ambient temperatures will be −30° C (−22° F) or lower, manually elevate engine speed to 1575 rpm except on 336E machines. The 336E has a direct drive fan so engine speed should be kept as low as possible to avoid overcooling.

• Make sure that the parking brake is engaged or the hydraulic lock lever is disengaged to assure an automatic regeneration has the best opportunity to complete during an extended idle event.

• Turn off the cab heater. Turning off the cab heater will help keep more heat in the engine.

• Install tarps to the engine enclosure. Refer to Service Magazine, SEPD1387 for tarp installation instructions on 336E machines. Tarps will have to be fabricated for other applications.

• Perform the Service Letter associated with the thermostat update on D6T and D7E applications. The Service Letter contains an update to the thermostat which is "non-vented". The previous thermostat had a vent hole incorporated into the design. In colder climates, this change would allow some coolant to flow through the cooling system even though the thermostat was closed. The new thermostat for the D6T and D7E must NOT be used on other C9.3 applications.

Through onsite testing in Canada and North Dakota, these steps have been shown to keep the system at an acceptable temperature on D6T, D8T, 140M Series 2, 160M Series 2, and 336E machines. The effect on other models is currently unknown, but directionally is the proper way to increase likelihood of keeping the engine coolant temperature warm enough to initiate regenerations.

Related Information on Regeneration Requirements

In order for the regeneration system to activate when the machine is left idling, the following conditions must be met:

• The parking brake must be engaged on wheeled machines or track type tractors. The hydraulic lock lever must be disengaged on hydraulic excavators.

• No active fault codes are present for the ARD fuel system, ARD air system, ARD ignition system, or DPF intake.

• The DPF intake temperature is greater than 50° C (122° F)

• If the ambient air temperature is less than 0° C (32° F), the coolant temperature must be 60° C (140° F) or greater

• If the ambient air temperature is greater than 0° C (32° F), the coolant temperature must be 40° C (104° F) or greater

DPF Soot Load Backup Timer

Caterpillar has also received reports of some machines that have suffered the above mentioned issues also experiencing a rapid soot increase on the soot gauge. Caterpillar is investigating whether the DPF delta P sensor and intake pressure sensor line freezing may be contributing to this issue. But, the issue is more likely that the backup timer strategy for DPF soot load is activating the rapid soot increase.

What is the backup timer strategy?

The strategy is in place to protect against long periods of operation where the soot level is not brought down to 0 percent. The soot level being brought down to 0 percent allows the ECM to recognize that the DPF is clean. If the machine is performing frequent partial regenerations and keeping soot load percent within an allowable range, the strategy will begin to lose confidence in the amount of soot that is being measured by the delta P sensor or soot model. In these cases, regeneration needs to take place that gets soot load percent down to zero. This regeneration allows the soot model and timers to reset. There are two timer thresholds that will do different things to the system:

• Timer threshold #1: activates once the timer reaches 12 hrs without a regeneration being performed that brings soot load percent to zero. If soot load percent is less than 60 percent when this event happens, the soot level gauge will quickly increase to 60 percent. This increase on the gauge will then allow both low and high speed automatic regenerations to take place.

• Timer threshold #2: activates once the timer reaches 18 hrs without a regeneration being performed that brings soot load percent to zero. Soot load will quickly increase to 100 percent soot load to activate the E995 (2) or 3719-16 code. These codes are used to notify the operator that a regeneration is needed. When this timer threshold is reached, the DPF lamp will not remain illuminated until a regeneration is completed and soot load percent is brought to zero.