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A friend is getting a P1602 error. He bought a reprogrammed PCM and is still getting the same error. Now he wants to know if it's the ECM that's causing the problem. The truck makes a cranking sound but won't start. Dash panel lights come on but none of the gauge needles move. FYI, the problems started after the truck was jump started.
Was original PCM dead? Has the 'new' PCM been working at all? The p1602 DTC is set when the battery voltage was detected as low or disconnected. Do the basics and check the battery terminals are clean and tight and that he engine has a good earth lead to the body. Check that battery voltage is 12.4v or higher. Check the fuses and relays. Clear the code and retry to start. If possible try the 'old' PCM if it was working before being swapped out.
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Without testing ,hard to say for sure . Gauge could be going bad or the engine coolant temp sensor , wiring for sensor , PCM/ECM etc..... Knowing where that info originates an how it gets to the instrument cluster gauge is key in diagnosing the problem . Having worked at GM dealer ships an having correct tools an information gives me an edge over most . Most people would just replace parts an hope it fixes it . The first place to start would be to hook up a factory or professional scan tool an check for DTC'S - diagnostic trouble codes in the instrument cluster an the PCM/ECM . View live data inputs from the coolant temp sensor to the PCM?ECM - engine computer ,also see if that same info is getting to the instrument cluster . Most usually , if the problem is happening at the time we can't find the fault .
The Coolant temp sensor is an input to the PCM , the PCM sends this if to the instrument cluster on the serial data network . Don't know if you know what that is ?
Engine Coolant Temperature Gage
The instrument panel cluster (IPC) displays the engine coolant temperature as determined by the engine control module (ECM). The IPC receives a serial data message from the ECM indicating the engine coolant temperature. The engine coolant temperature gage defaults to 100°F (40°C) or below if:
• The ECM detects a malfunction in the engine coolant temperature sensor circuit.
• The IPC detects a loss of serial data communications with the BCM.
• The BCM detects a loss of serial data communications with the ECM.
GM did have problems with stepper motors inside instrument clusters 2003 to 2006 . Stepper motors are what control the gauge needles . https://www.youtube.com/watch?v=oTm2oDx-_GM
Did you check the fuse that supply's battery voltage to pin # 16 at the DLC - diagnostic link connector ? That's where you plug your code reader in . The lighter fuse - 15 amp located in the under hood fuse box supply's battery voltage to pin #16 . The fuel gauge not working could be any one of a number of thing's , without testing an checking for DTC'S - diagnostic trouble code's I would only be guessing . Checking code's in the instrument cluster an PCM should be done by a qualified repair shop. The fuel level sending unit in the fuel tank is a direct input to the PCM/ECM - engine computer , the PCM / ECM sends this info too
The instrument panel cluster (IPC) displays the fuel level as determined by the powertrain control module (PCM)/engine control module (ECM). The IPC receives a GMLAN message from the body control module (BCM) indicating the fuel level volume. The fuel gage defaults to empty (E) if:
• The PCM/ECM detects a malfunction in the fuel level sensor circuit.
• The IPC detects a loss of GMLAN communications with the BCM.
When the fuel level is less than a certain low percentage, LOW FUEL message displays in the driver information center (DIC).
Odometer
The vehicle odometer is calculated and stored electronically in the body control module (BCM) and is sent via GMLAN to the instrument panel cluster (IPC) for display. The BCM calculates and stores the mileage based on the vehicle speed GMLAN message from the powertrain control module (PCM)/engine control module (ECM). The IPC displays the season odometer information from the BCM in the driver information center (DIC). The odometer will display error if the IPC detects an invalid odometer data from the BCM. After an invalid odometer data is received from the BCM, the IPC will display the last known odometer reading for 1.5 seconds before error is displayed in the DIC.
A code P0601 in most cases means the PCM has gone bad. This is possibly due to a short-circuit inside the PCM. Or, if you disconnect the wires/connector from the PCM while the battery is still connected, that may also cause this code. the most common fix is to replace and reprogram the PCM. In a few cases the dealer may be able to reflash the PCM and get it working. But more than likely the PCM will need to be replaced and reprogrammed dealership for this). The good news is it *may* be covered under your emmissions warranty. good-day!
If you key has a chip in it, you will probably have to get your ECM reprogrammed with the proper VIN, since it no longer matches the original VIN on your Vehicle. I don't think the dealer would program your keys to a mismatched VIN number, so more than likely you will need your ECM reprogrammed with the proper VIN. This will need to be taken to the Dodge Dealership to be fixed.
The ECM (Electronic control module) runs the engine and the emission control system, the BCM (Body control module) operates most electrical body functions like wipers and interior lights and power windows and door locks plus the security system in may cases, the ECM (on this car now known as the PCM since 1996 by federal mandate) can be flashed, which just a reprogramming of the EPROM chip
P0601 - Internal Control Module Memory Check Sum Error
Basically that means that there is an interal fault in the Powertrain Control Module (PCM). There have been many reported PCM failures on Chrysler/Dodge products although it is possible for this to happen on any vehicle. In Dodge/Chrysler products, a P0601 trouble code means that a serial communication failed inside the computer at least 6 times.
Symptoms: Likely, no symptoms will be discernible to the driver, other than the illuminated Check Engine Light. Typically the engine runs fine, gauges work, etc.
Causes: A code P0601 in most cases means the PCM has gone bad. This is possibly due to a short-circuit inside the PCM. Or, if you disconnect the wires/connector from the PCM while the battery is still connected, that may also cause this code.
Possible Solutions: With a P0601 OBD-II trouble code, the most common fix is to replace and reprogram the PCM. In a few cases the dealer may be able to reflash the PCM and get it working. But more than likely the PCM will need to be replaced and reprogrammed (we recommend you take it to a dealership for this). The good news is it *may* be covered under your emmissions warranty. So even if you're out of bumper-to-bumper warranty or powertrain warranty, check your warranty guide or dealer to see if this is covered.
Other people have reported that they cleared the code only for it to return again and again. Keep in mind that most shops can replace the PCM but not all can program it.
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