DTC P0237: Manifold Absolute Pressure (MAP) Sensor Circuit Low Voltage Check the ''On Board Diagnostic (OBD) System Check''. Was the ''OBD System Check'' performed? YES – Go to step 2. NO – Go to OBD System Check. Check the DTC. Are there any other (beside DTC P0237) being output? YES – Go to relevant DTC chart. NO – Go to step 3. Check the DTC. Are there other DTCs P1627, P1618 (beside DTC P0237) being output? YES – Go to DTC P1627, P1618 chart (5 V reference #2 circuit failure). NO – Go to step 4. Turn the ignition switch ON (II). Check the MAP with the scan tool. Is about atmospheric pressure indicated? YES – Go to step 6. NO – Go to step 8. Start the engine and allow it to idle. Check the MAP with the scan tool. Is about 20 – 30 kPa (150 – 225 mmHg, 5.9 – 8.9 in. Hg) indicated? YES – Intermittent failure, system is OK at this time. Check for poor connections or loose wires at the MAP sensor and at the ECM. NO – Go to step 8.

Check for the following conditions: Damaged MAP sensor The vacuum hose work at MAP sensor for leaks The PCV system vacuum leaks An incorrect PCV valve Vacuum leaks in EGR valve flange and pipes Intake manifold vacuum leaks Is a problem found? YES – Repair as necessary. NO – Go to step 9. Turn the ignition switch OFF. Disconnect the MAP sensor 3P connector. Measure voltage between the MAP sensor 3P connector terminals No. 1 and No. 3. Wire side of female terminals MAP sensor 3P connector Is there about 5 V? YES – Replace the MAP sensor. NO – Go to step 12. aaa