Paccar EGR Disabled triggered SPN 411 P1495 P1496 Explainer (3-minute read)

The fault codes related to P1495/P1496 mean that the engine protection has been enabled causing the EGR to be disabled and the system to go into preventative safety measures. As a result, passive/active DPF regeneration is disabled as well. When a problem arises, you have 10 hours to fix the problem or else it goes into an EGR derate. 

This EGR derate on a Paccar limits your engine power up to 25-40%. The loss in power will prompt you to seek service at a repair shop or dealer. 

What causes P1496 to become active? 

This fault code is an indication that there is a problem with another fault code that triggers a derate. So, this fault code alone is not enough to fix it. There is actually more to the story as to why your P1496 fault code came on.  

Troubleshooting this fault code is crucial. It is crucial because you want to ensure you will have full power while driving and to confirm that your regeneration system is working normally. This fault code is not easy to trace, which is why it is imperative to go through the troubleshooting steps so that this problem does not come back.  

The following fault codes are specific instigators of the P1496 fault code: 

P0046 P0069 P0070 P0071 P0072 P0073 P0107 P0108 P0110 P0112 P0113 P0115 P0116 P0117 P0118 P011A P0128 P0201 P0202 P0203 P0204 P0205 P0206 P0217 P0261 P0262 P0263 P0264 P0265 P0266 P0267 P0268 P0269 P0270 P0271 P0272 P0273 P0274 P0275 P0276 P0277 P0278 P0301 P0302 P0303 P0304 P0305 P0306 P0315 P0403 P0404 P0407 P0408 P0471 P0472 P0473 P0486 P0488 P0489 P0490 P0611 P062B P062D P0698 P0699 P1111 P1115 P1225 P1226 P1227 P1228 P1230 P1234 P1238 P1242 P1246 P1250 P1261 P1262 P1263 P1264 P1265 P1266 P1267 P1268 P1269 P1270 P1271 P1272 P1273 P1274 P1275 P1276 P1277 P1278 P1300 P1350 P1351 P1352 P1356 P1405 P1406 P1493 P1494 P1718 P1719 P171A P171E P171F P1720 P1723 P1724 P1725 P1727 P1961 P1962 P1964 P1965 P1967 P1968 P1970 P1971 P1973 P1974 P1976 P1977 P2147 P2148 P2150 P2151 P2227 P2228 P2229 P2425 P2457 P2563 P3768 P3769 P3772 P3773 P3774 P3775 P3779 P3780 P3781 P3782 P3784 P3785 P3786 P3787 P3789 P3790 P3793 P3794 P3966 U0157 U1014 U104C U104D U1157 U1159  

^^^^ So you must fix these fault codes before the derate P1496 code can go away.  

What happens if this P1496 stays active?  

If this fault code is active for more than 10 hours, it triggers another fault code which is P1495 – EGR Disabled derate permanent.

How to clear P1495 – EGR Disabled Derate permanent? 

If P1495 is the fault code that remains active you must use a dealer level capable tool such as Davie 4 software, OTR Diagnostics, or the OTR Reset Tool to clear it. P1495 is triggered if P1496 fault code has been active for more than 10 hours.  

Why does my truck show EGR Delta Pressure Fault on the dashboard?  

This notification comes from P1495 / P1496 and does not always mean you have an issue with your EGR Delta Pressure sensor. This just means you are in EGR derate and you have other issues that are triggering this derate.  

 

SPN 411 and SPN 4796 — What do these fault codes mean? 

You can’t rely on just a SPN number to diagnosis your issue.  

Kenworth & Peterbilt trucks display fault codes in SPN numbers without giving you FMI. The only way to properly diagnosis the SPN fault codes is to match them with the pcodes. The way to match them 100% is to have the SPN number and the FMI number. 

For example,  

SPN 411 = P1495 / P1496  
Most times there won’t be an issue with the EGR Delta Pressure sensor. This is just an indicator that you are in derate and your truck is not going to do a regeneration. It is recommended to connect to a diagnostic tool to read the exact pcode, or SPN/FMI. You can use softwares like Davie 4, Jpro, Jaltest, and Texa. 

SPN 4796 = P3778 — Fuel dosing module — Degraded  
The EAS-3 ECU detects that the aftertreatment fuel dosing module has used up all compensation. Active DPF regeneration will be disabled. Possible ineffective regeneration of the DPF can result after the fault code has changed to active. This diagnostic runs during active regeneration of the DPF system. The EAS-3 ECU detects that the fuel dosing module cannot inject enough fuel for active regeneration of the DPF system.  

How to reset P3778 fault code: 

This fault code will change to inactive immediately after the diagnostic runs and passes. It is necessary to run a stationary regeneration or use DAVIE to clear this fault code. 

The most important thing to remember is that if P1496 fault code remains on for more than 10 hours then you need your EGR Derate reset which is caused by P1495. 

I hope this helps with some questions that seem to come up! 

Until next time! 👋
Stay safe, stay healthy & be blessed.