93 expo. my check engine lights goes on and then off. I had the codes checked but everyone says they are not getting a code or that the codes make no sense. It is checked when the light is on

Marvin

• 85242 Answers
• Posted on Oct 14, 2008

SOURCE: check engine code p1493. the

P1493 Battery Temp. Sensor, Low Voltage,Solution: have the Battery and the Alternator tested, Auto Zone and Kragen as well as others do this for free. I suspect your Alternator is the problem.

Harvey N Tawatao

• 3854 Answers
• Posted on May 02, 2009

SOURCE: CHECK ENGINE LIGHT ON CODE P0170

DTC P0170 applies to fuel trim malfunction on all 2.4L vehicles, 3.0L Federal vehicles and right bank (bank 1) on 3.0L California vehicles. 
DTC P0173 applies to fuel trim malfunction on left bank (bank 2) on 3.0L California vehicles.
DTC Set Criteria (2.4L)
Engine is in closed loop control. Intake air temperature is more than 14°F (-10°C). Barometric pressure is more than 11 psi (76 kPa). Volume Airflow (VAF) sensor output frequency is 88 Hz or more. Code will set if long-range fuel correction is less than -12.5 percent, or more than +12.5 percent, for 5 seconds and short-range fuel correction is less than -10 percent, or more than +10 percent, for 5 seconds. 

Engine is in closed loop control. Intake air temperature is more than 14°F (-10°C). Barometric pressure is more than 11 psi (76 kPa). VAF sensor output frequency is less than 88 Hz. Code will set if long-range fuel correction is less than -12.5 percent, or more than +12.5 percent, for 5 seconds. On 2.4L code will also set if short-range fuel correction is less than -15 percent, or more than +15 percent, for 5 seconds. On 3.0L Federal code will also set if short-range fuel correction is less than -13.5 percent, or more than +13.5 percent, for 5 seconds. 

Have the O2 Sensor changed on the Right Bank, ( passenger side of the Engine, or where the # 1 cylinder is.)
Good luck and hope this helps

SOURCE: Check Engine Light came on with code p0420. Dealer wants $3900 to fix "b2 manifold and front pipes. Does this make sense. Are their better alternatives. I left the dealership without fixing it and the

if u r have lexus or v 6 or v8 so change or check u r leak of exhouse bank #1 driver side if u all want any question send me mail [email protected]

SOURCE: Evaporative Emission System codes

check ur gas cap for tight and proper seal that is the most common problem for the the evap codes if cap is good check fuel and vent lines for damage or leaks from gas cap under vehicle up to engine compartment

SOURCE: 2001 Ford Taurus - Check engine light sporadic

what is the battery voltage with no headlights on and car running with a multimeter and your light on the dash on?
what is the voltage at battery with car running and headlights on with a multimeter?
It sounds like it is overcharging,