What Is Fault Code SPN 5488 FMI 5? (Freightliner, Detroit)
When you look at the official SPN code list, you will see they have categories for Freightliner, Detroit Diesel, and Cummins motors and there is an official SPN FMI list. However, all those lists are almost exactly the same. The SPN FMI fault codes work for all those brands and other ones.
The fault code SPN 5488 means - Scr Line Heater #5 Circuit Failed Open; Aftertreatment 1 Diesel Exhaust Fluid Line Heater 5 State Current Below Normal Or Open Circuit; Open Load On Function "am_pwm_line_heating_5" This is the Doser to Tank DEF line.
To learn more about this code, just continue to read our article. It has the information you want to know about so you can make the repair quickly. This fault code seems to only have 4 steps to resolve it which can be seen as good news.
Freightliner Code SPN 5488 FMI 5
Generally, when you see this fault code, it means that you have an open circuit somewhere in line #5. When the code is set you will see the MIL and CEL lights illuminated.
But when they are illuminated, you do not have to worry about any engine reaction, lowered performance, or even a derate signal. If those happen, then you have another problem and you have not seen the code yet.
For the Freight liner code option, you should only have about 4 steps to make the repair. Those steps are as follows:
“1. Disconnect and inspect line heater 5 harness connector. Inspect for signs of spread, damaged, corroded, bent, or unseated (pushed out) terminals, and signs of moisture or wire damage in the harness connector.
A. If any damage is found, repair as required. To verify repairs, run Output Component Test using Scan Tool with the latest software.
B. If no damage is found, go to the next step.
2. With ignition ON (engine OFF), measure voltage from line heater 5 harness side connector terminal 2 to battery ground. Inspect if the voltage is more than 11.5 Volts.
A. If more than 11.5 Volts, go to the next step.
B. If less than 11.5 Volts, repair wire from DEF line heater harness side connector terminal 2 to ACM 120-terminal connector terminal 39. Verify repairs by running Output Component Test using Scan Tool with the latest software.
3. With ignition OFF, disconnect ACM 120-terminal connector. Inspect for signs of spread, damaged, corroded, bent, or unseated (pushed out) terminals, and signs of moisture or wire damage in the harness Connector.
A. If any damage is found, repair as required. To verify repairs, run Output Component Test using Scan Tool with the latest software.
B. If no damage is found, go to the next step.
4. Measure resistance from line heater 5 harness side connector terminal 1 to ACM 120-terminal harness side connector terminal 16. Inspect if resistance is more than 5 Ohms.
A. If more than 5 Ohms, repair wire open from terminal 1 to terminal 16.
B. If less than 5 Ohms, replace line heater 5 (source)
That should be all you have to do with this engine model.
Detroit SPN 5488 FMI 5
With this engine model, the four steps listed above are the same. However, the Detroit Diesel data sheet adds 4 more steps for this engine brand. The missing 4 steps are:
5. Turn the ignition OFF
6. Disconnect the ACM 120-pin connector.
7. Inspect the harness connector for signs of damaged, bent, spread, corroded, or unseated (pushed out) pins and signs of moisture in the connector or wire damage near the connector.
A. If signs of damage are present, repair as necessary. Using DiagnosticLink, perform Output Component Test to verify repairs.
B. If no signs of damage are present, Go to step 8.
8. Measure the resistance between pin 1 on the line heater 5 harness side connector and pin 16 of the ACM 120-pin harness side connector.
A. If the resistance is greater than 5 ohms, repair the open wire between pin 1 on the line heater 5 harness side connector and pin 16 of the ACM 120-pin harness side connector. Refer to Original Equipment Manufacturer (OEM) literature for schematic information.
If the resistance is less than 5 ohms, replace line heater 5. Refer to the section "Removal of the GHG14 Diesel Exhaust Fluid Lines". (source)
Here is a diagram of line #5:
**Image taken from this link- https://f01.justanswer.com/roybelding/5b72ad74-e0ab-4f3c-87d2-6c6dc00231fd_5488.JPG
Do a Visual Inspection
When it comes to electrical fault codes, this is one of the more common instructions you have to follow. Often, it is the hard components that will have the ECM set this code.
When you have SPN 5488 FMI 5, 4, or possibly 3, you need to do a visual inspection before doing much else. The source of the problem could be a broken wire, damaged pin, loose connection, frayed wire, and so on.
Not every fault code will have a lot of high technology behind it. Sometimes, the problem is solved by doing old-fashioned mechanical work. This is done by just looking at the components involved.
If all of these needed components are in fine shape then you can move on to the more complicated newer technology repairs. You always want to deal with the easiest possibilities first.
That way you save a lot of time and money by avoiding going to the shop or the dealers for help. It doesn’t take long for a visual inspection to take place.
Some Final Words
It seems that Cummins may not have an equivalent fault code for this series but if it does pop up, the repair should be the same as listed for the Freightliner and Detroit Diesel engines.
The codes may vary from time to time but when dealing with the same components, the actual repair steps are very similar. Just make sure you have the right tools in your toolbox so you can handle the repair if it is not that complicated or takes special tools to fix.
Sometimes you do end up at the mechanic's because of the specialized tools needed for repair work.
