Barometric sensor reading

Ramphele DL : At sea level, you’re looking at roughly 100 to 102 kPa, and even at the bottom of the Dead Sea (the lowest point on Earth), it doesn’t exceed 108 kPa. So, 199 kPa suggests either a serious sensor input error or a corruption in the ECU’s interpretation of the signal. On Jags of this era, the ECU performs a barometric pressure snap shot during key on before engine start, using the MAP sensor as the measuring device since there’s no separate BARO sensor. If the intake manifold or MAP port is contaminated, restricted, or sees abnormal pressure (like a stuck open EGR or boost control issue), it can skew this reading.

Ramphele DL : But more commonly, it’s a circuit issue check the 5V reference line to the MAP sensor for voltage spikes or resistance. I’ve seen cases where a failing alternator or poor grounding introduced enough electrical noise to make the ECU think it was under 2x atmospheric pressure. Verify the actual supply voltage at the sensor with the connector plugged in (back-probing), and ensure the ground is solid less than 0.2 ohms to battery negative.