The engine will reduce horsepower as a function of altitude to protect critical engine components. Power reduction starts at approximately 8700 ft on power ratings greater than 500 hp. Altitude is determined by barometric pressure. A faulty barometric pressure sensor could start a premature power reduction. Check the sensor.
| Baro (kPa) | Altitude (Ft) | Altitude (M) |
| 100.01 | 0 | 0 |
| 99.4 | 200 | 61 |
| 98.7 | 400 | 121 |
| 98.0 | 600 | 182 |
| 97.4 | 800 | 242 |
| 96.7 | 1000 | 303 |
| 96.1 | 1200 | 364 |
| 95.4 | 1400 | 424 |
| 94.8 | 1600 | 485 |
| 94.2 | 1800 | 545 |
| 93.5 | 2000 | 606 |
| 92.9 | 2200 | 667 |
| 92.3 | 2400 | 727 |
| 91.6 | 2600 | 788 |
| 91.0 | 2800 | 848 |
| 90.4 | 3000 | 909 |
| 89.8 | 3200 | 970 |
| 89.1 | 3400 | 1030 |
| 88.5 | 3600 | 1091 |
| 87.9 | 3800 | 1152 |
| 87.3 | 4000 | 1212 |
| 86.7 | 4200 | 1273 |
| 86.1 | 4400 | 1333 |
| 85.5 | 4600 | 1394 |
| 84.9 | 4800 | 1455 |
| 84.3 | 5000 | 1515 |
| 83.7 | 5200 | 1576 |
| 83.1 | 5400 | 1636 |
| 82.5 | 5600 | 1697 |
| 81.9 | 5800 | 1758 |
| 81.3 | 6000 | 1818 |
| 80.7 | 6200 | 1879 |
| 80.1 | 6400 | 1939 |
| 79.5 | 6600 | 2000 |
| 79.0 | 6800 | 2061 |
| 78.4 | 7000 | 2121 |
| 77.8 | 7200 | 2182 |
| 77.2 | 7400 | 2242 |
| 76.7 | 7600 | 2303 |
| 76.1 | 7800 | 2364 |
| 75.5 | 8000 | 2424 |
| 75.0 | 8200 | 2485 |
| 74.4 | 8400 | 2545 |
| 73.8 | 8600 | 2606 |
| 73.3 | 8800 | 2667 |
| 72.7 | 9000 | 2727 |
| 72.2 | 9200 | 2788 |
| 71.6 | 9400 | 2848 |
| 71.1 | 9600 | 2909 |
| 70.6 | 9800 | 2970 |
| 70.0 | 10000 | 3030 |
| 69.5 | 10200 | 3091 |
| 68.9 | 10400 | 3152 |
| 68.4 | 10600 | 3212 |
| 67.9 | 10800 | 3273 |
| 67.3 | 11000 | 3333 |
| 66.8 | 11200 | 3394 |
| 66.3 | 11400 | 3455 |
| 65.8 | 11600 | 3515 |
| 65.2 | 11800 | 3576 |
| 64.7 | 12000 | 3636 |
| 64.2 | 12200 | 3697 |
| 63.7 | 12400 | 3758 |
| 63.2 | 12600 | 3818 |
| 62.7 | 12800 | 3879 |
| 62.2 | 13000 | 3939 |
| 61.7 | 13200 | 4000 |
| 61.2 | 13400 | 4061 |
| 60.7 | 13600 | 4121 |
| 60.2 | 13800 | 4182 |
| 59.7 | 14000 | 4242 |
| 59.2 | 14200 | 4303 |
| 58.7 | 14400 | 4364 |
| 58.2 | 14600 | 4424 |
| 57.7 | 14800 | 4485 |
| 57.3 | 15000 | 4545 |
| 56.8 | 15200 | 4606 |
| 56.3 | 15400 | 4667 |
| 55.8 | 15600 | 4727 |
| 55.4 | 15800 | 4788 |
| 54.9 | 16000 | 4848 |
Table 1. Barometric Pressure
If your vehicle is operating above sea level, a loss of power will be encountered, no further troubleshooting is required.
If your vehicle is operating at or below sea level and there is a lack of power, refer to “10.10 Power Verification With Chassis Dynamometer” .
