The MAN TGM is a versatile medium-duty truck widely used in distribution and construction. Its instrument cluster provides critical warnings to ensure safe operation and prevent costly downtime. Understanding these signals helps drivers respond appropriately.
MAN TGM Warning Light Symbols
| Symbol | Name | Color | What it means | What to do |
|---|---|---|---|---|
| Master Warning (Stop) | RED | A critical fault has been detected in the MAN TGM that demands immediate shutdown to prevent damage or accident. | Stop the vehicle safely as soon as possible, engage parking brake, and turn off the engine. | |
| Master Caution | AMBER | The TGM's electronic system has identified a non-critical fault that requires attention at the next stop. | Check the multifunction display for specific fault codes and plan a service visit. | |
| Check Engine (MIL) | AMBER | The engine control unit has detected a malfunction in the emission or performance system of your MAN TGM. | Reduce load and speed, and schedule diagnostic check at a MAN workshop. | |
| Engine Oil Pressure | RED | Oil pressure in the TGM's D15 engine is below safe level, risking severe engine damage. | Stop immediately, check oil level, and do not restart until problem is resolved. | |
| Battery / Charging | RED | The alternator is not charging the battery properly, or voltage is out of range in your TGM. | Check belt tension and connections, and replace alternator if necessary. | |
| Coolant Temperature | RED | Coolant temperature in the TGM exceeds safe limits, risking engine overheating. | Stop engine immediately, allow to cool, check coolant level and fan drive. | |
| Transmission Temp | AMBER | The automatic transmission fluid in the TGM is running hot, usually due to heavy load or continuous stop-and-go. | Reduce load or shift to a lower gear to allow cooling; service if recurring. | |
| Brake System | RED | A fault in the brake system of your MAN TGM has been detected, possibly low air pressure or pad wear. | Stop safely, do not drive until the brake system is inspected and repaired. | |
| ABS | AMBER | The Anti-lock Braking System on the TGM has a fault; standard brakes still work but ABS is disabled. | Drive cautiously to a MAN service center and have the system diagnosed. | |
| Parking Brake | RED | The parking brake is engaged or there is a malfunction in the spring brake system of the TGM. | Release parking brake before driving; if light stays on, check air pressure and brake chambers. | |
| Tire Pressure (TPMS) | AMBER | One or more tires on the TGM have low pressure, affecting stability and fuel economy. | Check tire pressures and inflate to recommended level as soon as possible. | |
| Airbag (SRS) | AMBER | The supplemental restraint system on the TGM has a fault; airbags may not deploy in a crash. | Have the system inspected by a MAN technician immediately. | |
| Seat Belt | RED | Seat belt is not fastened while the TGM is in motion. Fasten to comply with safety regulations. | Fasten your seat belt immediately. | |
| Glow Plug / Preheat | AMBER | The glow plug system is active or faulty; on the TGM, it's a sign that the engine needs preheating in cold conditions. | Wait for the light to turn off before starting in cold weather; if it stays on, have the system checked. | |
| DPF / Regeneration | AMBER | The diesel particulate filter is clogged and needs regeneration; driving at highway speed may help clear it on the TGM. | Drive at 60+ km/h for 20 minutes to initiate regeneration; if light persists, visit a workshop. | |
| DEF / AdBlue | AMBER | AdBlue level is low or system fault; the TGM will eventually restrict power to protect emissions. | Refill AdBlue tank with approved fluid at the next stop. | |
| Water in Fuel | AMBER | Water has accumulated in the fuel filter/water separator of the TGM, which can cause injection damage. | Drain the water separator immediately; if light stays on, replace the filter. | |
| Low Fuel | AMBER | Fuel level in the TGM is critically low. Refuel to avoid running out. | Refuel as soon as possible. | |
| High Beam | BLUE | High beam headlights are active on the TGM. Dim your lights when approaching oncoming traffic. | Switch to low beam when other vehicles are near. | |
| Power Steering (EPS) | RED | Electric power steering system has failed on the TGM, requiring increased steering effort. | Stop safely and have the EPS system repaired before driving further. | |
| Reduced Power (Limp Mode) | AMBER | The engine control unit has limited power to protect components; the TGM will have limited acceleration. | Drive to the nearest MAN service center at reduced speed. | |
| Air Brake Pressure (Low) | RED | Air pressure in the brake system of the TGM is too low for safe braking. | Stop immediately and allow compressor to build pressure; check for leaks. | |
| Engine / Exhaust Brake | GREEN | The exhaust brake or retarder is active on the TGM to assist in slowing down. | Normal operation; disengage when not needed to avoid unnecessary wear. | |
| Trailer | GREEN | A trailer is electrically connected and recognized by the TGM's system. | Ensure trailer brakes and lights are functioning properly. | |
| Door Open | RED | A cab door on the TGM is open or not fully closed while the vehicle is moving. | Pull over safely and close all doors securely. | |
| High Exhaust Temp (HEST) | AMBER | Exhaust gas temperature is elevated, often during DPF regeneration on the TGM; avoid parking near combustibles. | Continue driving if safe; do not park over dry grass or flammable materials. | |
| Washer Fluid Low | AMBER | Windshield washer fluid level is low on the TGM; refill to maintain clear visibility. | Top up washer fluid at the next opportunity. |
27 symbols shown. Icons follow ISO 2575 dashboard standards; exact graphics vary by model year.
Most Important Warning Lights
Engine Overheating
Common causes
- Low coolant level
- Faulty thermostat
- Clogged radiator
What to do
Stop the TGM immediately, let the engine cool, check coolant reservoir, and top off if low. If recurring, inspect the cooling system for blockages or leaks at a MAN dealer.
Low Air Brake Pressure
Common causes
- Air leak in lines
- Faulty compressor
- Drained air tanks
What to do
Do not drive; allow the air compressor to build pressure. If pressure does not rise, check for visible air leaks with the engine running. Seek roadside assistance for repairs.
Engine Oil Pressure Loss
Common causes
- Low oil level
- Oil pump failure
- Worn bearings
What to do
Stop the TGM immediately and turn off engine. Check oil level and top up if needed. If light remains, do not restart; have the engine towed to a MAN workshop.
AdBlue System Malfunction
Common causes
- Empty AdBlue tank
- Faulty dosing injector
- Contaminated AdBlue
What to do
Refill with genuine AdBlue if low. If light persists, drive to a MAN dealer to diagnose the SCR system; continued driving may result in power limitation.
Electrical Charging Failure
Common causes
- Alternator belt slip or break
- Faulty alternator
- Battery connection issue
What to do
Check alternator belt tension; if broken, replace. If belt is okay, the alternator may need replacement. Avoid long trips until charging system is repaired.
Frequently Asked Questions
What does the flashing glow plug light mean on my MAN TGM?
A flashing glow plug indicator indicates a fault with the preheat or engine management system. On the TGM, it often points to a failing glow plug or a control unit error; have it diagnosed soon.
My MAN TGM shows 'DPF regeneration in progress' – should I stop?
No, continue driving if possible. The TGM's DPF regeneration requires highway speeds to burn off soot. If you must stop, the regeneration will pause and resume later. Avoid parking over dry grass.
Why does the 'Reduced Power' light come on when climbing a hill?
This is the TGM's limp mode, often triggered by high exhaust temperature or a DPF issue. Reduce load and shift down; if it persists, a diagnostic is needed.
How often should I drain the water separator on the TGM?
Check and drain the water separator every 10,000 km or monthly, especially in humid climates. The water-in-fuel light warns you to do it sooner.
The Master Warning light is on but no other lights – what to do?
This means a general fault has been logged. On the MAN TGM, scroll through the multifunction display to read the error code. If you cannot resolve it, visit a service center.
Can I drive with the ABS light on?
Yes, but cautiously. The standard brakes still work, but the ABS is disabled. On a slippery road, you may lose steering control during hard braking. Get it fixed as soon as possible.