answers
5 Answers
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HouseCallAuto 9/21/2012This car does not have a battery temperature sensor nor does it show a P1493 as an applicable code for this car. The code is a real code as you described it's title, it just does not apply to this car according to my information system. If your battery light is illuminated then it is likely that the alternator is junk. I believe that the code was misread and I would be surprised if you double checked and said again that the same code appeared. i checked two different information systems that are widely used in the industry and relied upon as giving correct information, neither of them showed a P1493 as applicable to a 2002 Stratus.The code is applicable to an older dodge intrepid, not Stratus.
josh 9/22/2012Actually it does apply to this vehicle as long as it's an 02 Stratus sedan with a 2.4L vin X. P1493- Ambient/Battery temperature sensor volts too low. If it's an 02 Stratus coupe with a 2.4L vin G then it doesn't apply. -
HouseCallAuto 9/22/2012I stand corrected by josh and inadvertantly looked up coupe with 2.4 G motor instead of sedan with X . thanks josh. I love your oversight. The battery temperature sensor is not serviced separately and if it is bad the pcm has to be replaced. I would clear the code and see if it returns before doing any repairs.
msb 9/24/2012Wish i read this before replacing my alternator... the battery and eng light still comes on... but anyway is the ambient temperature and the battery temperature sensor the same?
josh 9/25/2012The battery temperature is a calculated value(algorithm) based off of the ambient temperature sensor reading. Since the ambient temp sensor is close to the battery area the PCM uses it to infer some general(not exact) idea of battery temperature and uses this information to control generator output and maximum charging system efficiency. Since hot/cold batteries require different charging schedules it's very important that the PCM has this information.
msb 9/28/2012Replaced battery, alternator, pcm. Battery and engine light still on?
msb 9/28/2012What could be the problem?
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msb 9/28/2012Replaced battery, alternator and pcm. Battery light and engine light still on. What going on?
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HouseCallAuto 9/28/2012Is the alternator charging voltage between 13.5 and 14.5 volts? Can you confirm that you still have the same code - P1493 ? There is little diagnostic info for code P1493 except that the sensor (inlet air temp sensor) or (battery temp sensor) is within the PCM. I probably would have replaced the PCM also so don't feel bad about it. Your diagnostic should focus on the battery light being on and forget the P1493 for now. The battery light being on is related to the P1493, I just do not have a diagnostic strategy to apply yet. Need to know if the battery is charging or not. I suspect that there is a wiring problem either at the PCM or at the alternator or anywhere in between on the charging system wiring.
msb 9/29/2012Had battery checked. Reading alittle low but good to start car. Now code reads p1493 which says battery temp sensor high instead of low ( p1493). Any suggestions to which wiring may be problem?
HouseCallAuto 9/29/2012Please clarify, is the alternator charging voltage within the range I said? 13.5 to 14.5 volts. i need to know this. You said you checked the battery. checking the battery is not alternator charging voltage.
msb 9/29/2012Yes as i stated on 9/21 alternator at 13.9
HouseCallAuto 9/29/2012Thank You, sometimes I forget that there is prior posts to check. I have to work on this. I will post try to post a productive post in a day or two. rarely do I have to say that but this is an odd one. I will check with my master.
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josh 10/3/2012Here is what I want you to do, no exceptions. Either go to a shop with a capable scan tool(preferrably the DRBIII) or invest in a scan tool of your own. Either way, I NEED to know what the ambient temp sensor voltage pid reads in the PCM data stream, the battery temperature is just a PCM calculation based on this sensor input. The PCM controls the generator field in accordance with many inputs and the battery temperature is an important one. A lot of expensive parts have been needlessly shot-gunned onto this vehicle, lets do some real testing now please. That may sound harsh but I hate parts tossing.
From Alldata:
BATTERY TEMPERATURE SENSOR
The PCM uses the temperature of the battery area to control the charge system voltage. This temperature, along with data from monitored line voltage, is used by the PCM to vary the battery charging rate. The system voltage is higher at cold temperatures and is gradually reduced as temperature around the battery increases.
The ambient temperature sensor is used to control the battery voltage based upon ambient temperature (approximation of battery temperature). The PCM maintains the optimal output of the generator by monitoring battery voltage and controlling it to a range of 13.5 - 14.7 volts based on battery temperature.
The battery temperature sensor is also used for OBD II diagnostics. Certain faults and OBD II monitors are either enabled or disabled depending upon the battery temperature sensor input (example: disable purge and EGR, enable LDP). Most OBD II monitors are disabled below 20°F .
josh 10/3/2012Also from Alldata:
SYMPTOM
P1493-AMBIENT/BATT TEMP SEN VOLTS TOO LOW
WHEN MONITORED
The ignition key ON.
SET CONDITION
Ambient Temperature Sensor is less than 0.98 volt at the PCM for 5 seconds .
POSSIBLE CAUSES
Intermittent Condition
Ambient Temperature Sensor Internal Failure
Ambient Temperature Sensor Signal Shorted To Ground
Ambient Temperature Sensor Signal Shorted To Sensor Ground Circuit
PCM Terminal Condition
PCM
