COVER 2735198 - Caterpillar

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
Two engine harness routing issues are causing problems with the mass air flow sensor circuit and Diesel Particulate Filter (DPF) differential pressure circuit. These problems are typically routing issues with the wires pulled tight at the sensor connector.The following diagnostic codes are indicators of an engine harness issue at the mass air flow sensor:
171-3 Ambient Air Temperature: Voltage Above Normal
171-4 Ambient Air Temperature: Voltage Below Normal
132-3 Engine Inlet Air Mass Flow Rate: Voltage Above Normal
132-4 Engine Inlet Air Mass Flow Rate: Voltage Below NormalThe following diagnostic codes are indicators of an engine harness issue at the DPF differential pressure sensor:
3251-3 Aftertreatment #1 DPF Trap Differential Pressure: Voltage Above Normal
3251-4 Aftertreatment #1 DPF Trap Differential Pressure: Voltage Below Normal
523602-0 Aftertreatment Frequency Regeneration: HighThe 523602-0 Aftertreatment Frequency Regeneration: High occurs when there are three active regenerations within a 30 minute time frame. For those machines that have early hours, this code can be caused by faulty voltages in the DPF differential pressure sensor circuit. One of the triggers for an active regeneration is high DPF differential pressure. It has been confirmed that intermittent wiring issues in that circuit are causing the Engine ECM to falsely believe the DPF is full.Refer to Troubleshooting, UENR3423, "General Information and Regeneration Levels of the Diesel Particulate Filter (DPF)" for how the DPF Differential Pressure Sensor can trigger an active regeneration.Note: Most of the time the 523602-0 code is accompanied by the 3251-3 or 3251-4 code. Although not as common, the 523602-0 code can occur by itself. When a 523602-0 code occurs, the code will remain as an "Active Event" until the "Time Interval Reset" is performed in Caterpillar Electronic Technician (ET). This reset will change the code to logged. Caterpillar highly recommends clearing the code.To clear the code, the Key Switch must be OFF with the engine NOT running. The Troubleshooting manual is currently being updated with this code and other codes that are not in the manual. The Troubleshooting manual is to be completed by the end of May.Caterpillar recommends contacting your dealer TC on machines that have the 523602-0 code.If there are concerns that the DPF is full, submit a DSN ticket.For 308E2 machines with a serial prefix of S/N:TMX machines also do the following:
Check for broken or loose 436-0808 Bolts in the 436-2906 Exhaust Filter and Mounting Gp .Broken or loose bolts could cause increased vibration of the DPF differential pressure sensor circuit.
If a broken or loose bolt is found, replace all four bolts and washers with 9X-8912 Bolts and 7X-7729 Washers .
Submit an e-mail to Rob McHardy at the following email address providing the machine serial number, service hours, an attachment of a Product Status Report (or state which of the 523602-0, 3251-3, 3251-4 codes were present), and whether the bolts were found loose.This information will help determine the root cause.Robert_McHardy_Wc_a_t
Solution
Install the jumper