The RAM Cummins 5500 is a heavy-duty diesel work truck equipped with a 6.7L Cummins engine, featuring an array of warning lights critical for monitoring engine, emissions, and safety systems. Understanding these indicators helps prevent breakdowns and costly repairs, especially under heavy load or off-road conditions.
RAM Cummins 5500 Warning Light Symbols
| Symbol | Name | Color | What it means | What to do |
|---|---|---|---|---|
| Check Engine (MIL) | AMBER | The ECU has detected a fault in the engine, emissions, or fuel system specific to the Cummins 6.7L, such as a sensor reading abnormality or exhaust gas recirculation issue. | Reduce load and have the truck scanned with a diesel-specific diagnostic tool; continued driving may trigger reduced power. | |
| Glow Plug / Preheat | AMBER | Glow plugs are heating the intake air for cold starting; the light turns off when the grid heater is ready on this 6.7L Cummins. | Wait for the light to extinguish before cranking the engine; if it flashes, check glow plug relay or module. | |
| Water in Fuel | RED | Water has been detected in the fuel/water separator; water can damage the high-pressure fuel system on the Cummins 6.7L CP4 pump. | Drain the water separator immediately or replace the filter; do not run if sediment is visible. | |
| DPF / Regeneration | AMBER | The diesel particulate filter needs active regeneration; the exhaust temperature will rise to burn off soot, a normal process for the 6.7L Cummins. | Drive at highway speeds for 20-30 minutes to complete regen; if light stays on, forced regen or cleaning may be needed. | |
| DEF / AdBlue | AMBER | DEF level is low or quality issue detected; the SCR system requires DEF to reduce NOx in the 6.7L Cummins. | Refill with approved DEF; if light remains, check DEF heater or sensor, otherwise engine power will derate. | |
| Brake System | RED | A fault in the hydraulic brake system, low brake fluid, or electronic brake distribution issue on the RAM 5500. | Check brake fluid level and inspect for leaks; do not drive until brakes are fully functional. | |
| ABS | AMBER | Anti-lock brake system malfunction; standard brakes still work but ABS will not engage during hard stops on the RAM 5500. | Have the ABS module and wheel speed sensors checked; the truck is driveable but avoid slippery conditions. | |
| Airbag (SRS) | RED | Supplemental restraint system fault; airbags may not deploy in a collision on this heavy-duty chassis. | Take to dealer immediately for diagnostic; do not delay as safety is compromised. | |
| Seat Belt | RED | Driver or passenger seat belt is not fastened; chime may accompany on the RAM 5500. | Fasten seat belt for all occupants; if light persists with belt fastened, check buckle sensor. | |
| Tire Pressure (TPMS) | AMBER | One or more tires are significantly underinflated; the RAM 5500's TPMS uses wheel speed sensors. | Check and inflate all tires to recommended pressures; if light flashes, sensor battery may be low. | |
| Battery / Charging | RED | Alternator not charging or battery voltage low; the Cummins 6.7L relies on high amperage for starting and glow plugs. | Check belt tension and battery connections; do not shut engine off until charging is verified. | |
| Engine Oil Pressure | RED | Engine oil pressure is critically low; the 6.7L Cummins requires 10-60 psi depending on RPM. | Stop engine immediately; check oil level and look for leaks; do not restart until resolved. | |
| Coolant Temperature | RED | Engine coolant is overheating; the 6.7L Cummins operates around 190-200°F; above 230°F is critical. | Reduce load and idle to cool; if persists, pull over and check coolant level and fan operation. | |
| Transmission Temp | RED | Transmission fluid temperature is too high (over 250°F), common when towing heavy loads with the RAM 5500's 68RFE or Aisin. | Stop and idle in neutral to cool; avoid high-load operation until temperature drops. | |
| High Beam | BLUE | High beam headlights are engaged on the RAM 5500. | Dim when approaching oncoming traffic to avoid glare. | |
| Parking Brake | RED | Parking brake is engaged; may appear with a message if the brake is dragging. | Release parking brake fully before driving; if light stays, adjust or repair cable. | |
| Reduced Power (Limp Mode) | AMBER | ECU has limited engine power to protect the 6.7L Cummins, often due to emissions or sensor faults. | Have diagnostic codes read; common causes include DPF, DEF, or pedal position sensor issues. | |
| Trailer | GREEN | Trailer is connected and turn signal is working; on RAM 5500, it indicates trailer lighting connection. | No action if towing; if light flashes without trailer, check trailer wiring harness. | |
| Door Open | RED | A door, hood, or tailgate is ajar on the RAM 5500. | Check and close all doors securely; if light persists, check latch sensors. |
19 symbols shown. Icons follow ISO 2575 dashboard standards; exact graphics vary by model year.
Most Important Warning Lights
Check Engine (MIL) with Flashing
Common causes
- Catalytic converter damage risk
- Severe misfire or fuel system fault
- Excessive exhaust temperature
What to do
Immediately reduce load and pull over; do not drive more than a few miles. Have the 6.7L Cummins scanned for codes; flashing requires urgent dealer visit to prevent catalyst damage.
Water in Fuel
Common causes
- Contaminated fuel source
- Condensation in fuel tank
- Faulty fuel cap or seal
What to do
Drain the water separator (located on the fuel filter housing on the Cummins 6.7L) immediately; if water reoccurs, inspect fuel tank for rust or replace fuel filter.
DPF Exceeds Limit (Regen Not Possible)
Common causes
- Frequent short trips preventing regen
- Faulty EGT sensor
- Clogged DPF due to oil consumption
What to do
Perform a forced regeneration at a dealer or using a professional scanner; if DPF is blocked, it may need replacement. Avoid prolonged idling on the RAM 5500.
Brake System Warning (Red)
Common causes
- Low brake fluid level
- Leak in hydraulic lines or wheel cylinders
- Worn brake pads or rotor damage
What to do
Check brake fluid reservoir; if low, top off and inspect for leaks. Do not drive until brakes are firm; the RAM 5500's heavy load requires fully functional brakes.
DEF Quality or Level Critical
Common causes
- Running out of DEF
- Contaminated DEF (e.g., with diesel)
- DEF heater or quality sensor failure
What to do
Refill with fresh DEF that meets ISO 22241; if light remains, the SCR system may need to be flushed. Engine power will be limited until issue is resolved.
Frequently Asked Questions
Why does the glow plug light stay on for a long time in cold weather?
The 6.7L Cummins uses a grid heater instead of traditional glow plugs; in extreme cold, the heater may cycle longer to ensure starting. If it stays on continuously, the grid heater relay or module may be faulty.
Can I drive with the DPF regen light on?
Yes, active regen is a normal process; drive at highway speeds for 20-30 minutes to complete it. If the light turns to a flashing or a different warning, stop and seek service to avoid DPF clogging.
What does the water in fuel light mean on a RAM 5500?
It indicates water accumulation in the fuel/water separator, which can damage the high-pressure CP4 pump. Drain the separator immediately using the valve on the filter housing.
Why is my reduced power light on after refilling DEF?
The SCR system may take several ignition cycles to reset; drive a few miles. If it persists, the DEF quality sensor may need calibration or replacement.
How do I perform a forced DPF regen on a RAM 5500?
You need a compatible scan tool (e.g., WiTECH or aftermarket) to initiate a stationary regen. Follow the tool's instructions; ensure the truck is parked with adequate clearance due to high exhaust temps.
Can a bad battery cause warning lights on the dash?
Yes, low voltage can trigger multiple random lights (e.g., ABS, airbag, check engine). The 6.7L Cummins requires a healthy battery to power glow grid and sensors; test battery and alternator.