1999 Toyota Camry, 4 Cyl, Automatic - Was driving down the interstate at 70 mph, the check engine light came on, and the car started losing speed, as I mashed the gas pedal it would appear to die and then as I let off the gas pedal it would momentarily revive. This happened for about 4 or 5 times until finally the speed had reduced enough that the car died completely and has not started since. After getting it towed home, I checked the 4 spark plugs and they get good spark. I borrowed a code scanner and found there was a fault with the MAP sensor and with the Camshaft Position Sensor. What should I do next? Would simply replacing the sensors fixed the problem or are they just indicators for the real problem?

 

I would certainly test those two sensors before replacing, especially their connectors for tight fit. A code on one may have triggered the code on the other. You will need an ohm meter. Because the engine seemed to recover a little when you let thegas off I'd suspect the MAP more than the camshaft position sensor. It's odd that both would fail at the same time. You can access the test procedures from the manual link posted on this forum a little while back.

http://www.camrymanuals.com/

 

Thanks Pedro, I will get an ohm meter and check the sensors today.

 

i say u just replace them becaue your car is a 99 after all these years it decides to get loose on you, i dont think so, but i have to give the benefit of the doubt, check them you don't lose anything by checking them

 

Pedro,
I just checked the MAP sensor with a voltmeter and a vacuum pump at all 5 of the check pressures given in my manual the voltage was reading to high. I also checked the reference voltage from the PCM to the MAP sensor and it read 4.99 which is within parameters. So where do I go from here?

 

Pedro,
I just checked the MAP sensor with a voltmeter and a vacuum pump at all 5 of the check pressures given in my manual the voltage was reading to high. I also checked the reference voltage from the PCM to the MAP sensor and it read 4.99 which is within parameters. So where do I go from here?

Also the fittings were tight and there were no cracks in the vacuum lines

 

How far off were the voltage drops? Did the manual say what to do if voltages were off? Did you check the camshaft position sensor as well? If not I'd check that too.

 

I made a mistake today in checking the MAP sensor, I misunderstood (pain pills) the instructions and I was checking the voltage at the map sensor while using the vacuum gauge and not at the ECI/PCM ports, so I may need to go to Autozone tomorrow and borrow the vacuum pump again. But tonight I checked all the relays, the EFI and the Cir Opn Relay and they both worked. I am not getting power to the blue lead to the fuel pump therefore it is not coming on. I have checked all the fuses that I can find that have anything to do with the fuel pump and they are all good. Does the MAP sensor control power to the fuel pump. I have checked the white lead (ground) to the fuel pump and the ground is good. What controls power to the blue power wire to the fuel pump? With the fuel pump not running that is probably why it died on the highway and won't start now. And did I mention that I was on my way home from the hospital when the car died. I had been in for 4 days because of major surgery to remove 18 inches of my colon and repair some infection that had spread to my bladder. So I have been doing all this work today with 35 staples in my stomach and barely able to bend over. But hey, I didn't deal the cards, I am just playing them the best way that I can. Thanks for your assistance.

 

The MAP does not control the fuel pump. The ECU sends a 5V signal to the MAP and the MAP will return a variable voltage back to the ECU depending on manifold vacuum. The ECU will then determine fuel needed. Usually the MAP can cause rough running if it fails, not complete a complete shutdown.

The manual link I gave you also has electrical diagrams andalsoa fuel pump test procedure. I would check the cam position sensor as well. At this point I would concentrate on the fuel pump first and see if you can get it running. If it runs why don't you rest for now then clear the codes and see if they come back.

 

Today I ran a hot lead from the battery to the fuel pump and it spun just fine. I attempted to start the car while it was spinning but it wouldn't start. The MAP sensor turned out to be within parameters, so there is no problem there. One of the guys at the parts store said he thought it was in the distributor and that is why the camshaft position sensor faulted. Do you think there is anything to that?