Engine Performance problem
2000 Buick Lesabre 6 cyl Two Wheel Drive Automatic 235678 miles
mass air flow or volume air flow circuit low input
keeps coming back after we clear it
have new battery spark plugs fuel filter new mass airflow sensor new gas cap cleaned body throttel and still runs like crap any suggestions would be greatly appreciated
Before performing the procedures, check for vacumn leakages between the MAF and throttle body.
DTC P0102: MAF SENSOR CIRCUIT - LOW FREQUENCY
Mass Airflow (MAF) sensor measures amount of air entering engine during a given time. PCM uses MAF sensor information for fuel delivery calculations. MAF sensor readings during acceleration are much higher than those during deceleration or idle.
PCM calculates what MAF sensor reading should be received from sensor under certain conditions using engine speed (RPM), throttle position, and altitude parameters. When certain test conditions are met, PCM will compare its calculated MAF value to actual value received from sensor. If MAF sensor signal frequency is less than 1200 Hertz (Hz), DTC will set.
For duplication of DTC, ensure engine is running, system voltage is greater than 8 volts, and TP
sensor angle is less than 50 percent.
1. Perform On-Board Diagnostic (OBD) system check. After performing OBD system check, go to next step.
2. Start and operate engine at idle. Using scan tool, monitor MAF FREQUENCY. If frequency is less than 1200 Hz, go to step 4. If frequency is not less than 1200 Hz, go to next step.
3. Turn ignition on, engine off. Using scan tool, read and record FAILURE RECORDS data. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS. Using scan tool, read SPECIFIC DTC. If scan tool indicates that this DTC FAILED THIS IGN, go to next step. If DTC FAILED THIS IGN is not displayed, see DIAGNOSTIC AIDS.
4. Check for MAF sensor inlet screen blockage. Check for vacuum leaks at intake manifold, throttle body or EGR valve flange and pipes. Check for PCV valve faulty, missing or incorrectly installed. Repair as necessary. After repairs, go to step 14. If no problems are found, go to next step.
5. Turn ignition off. Disconnect MAF sensor connector. Turn ignition on, with engine off. Using DVOM, measure voltage between MAF sensor harness connector signal circuit and chassis ground. If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 9.
6. Connect a test light between MAF sensor harness connector ignition feed and ground circuits. If test light illuminates, go to step 8. If test light does not illuminate, go to next step.
7. Connect test light between MAF sensor harness connector ignition feed circuit and battery ground. If test light illuminates, go to step 10. If test light does not illuminate, go to step 11.
8. Check for faulty connection at MAF sensor. Repair as necessary. After repairs, go to step 14. If connection is okay, go to step 12.
9. Check MAF sensor signal circuit between PCM and MAF sensor for open or short. Repair as necessary. After repairs, go to step 14. If circuit is okay, go to step 13.
10. Locate and repair open in the MAF sensor ground circuit. After repairs, go to step 14.
11. Locate and repair open MAF sensor ignition feed circuit. After repairs, go to step 14.
12. Replace MAF sensor. After replacing sensor, go to step 14.
13. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
14. Turn ignition on, with engine off. Using scan tool, read and record FAILURE RECORDS data, and then clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for DTC P0102. If scan tool indicates that this DTC FAILED THIS IGN, go to step 2. If scan tool does not indicate that this DTC FAILED THIS IGN, system is okay.
Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe scan
tool while moving all related harness and connectors. A change in scan tool display indicates fault location.
Check for plugged intake air duct or dirty air filter. A wide-open throttle acceleration from a stop should cause MAF reading on scan tool to increase from about 4-7 grams per second at idle to 100 grams per second or greater at time of 1-2 shift. If MAF reading on scan tool does not increase, check for restriction.